diff --git a/.env.test b/.env.test
index 761d0d9210690d..2f8c1afd6e26e7 100644
--- a/.env.test
+++ b/.env.test
@@ -1,5 +1,5 @@
-# Node.js
-NODE_ENV=tests
+# In test, compile the NodeJS code as if we are in production
+NODE_ENV=production
 # Federation
 LOCAL_DOMAIN=cb6e6126.ngrok.io
 LOCAL_HTTPS=true
diff --git a/.github/workflows/test-ruby.yml b/.github/workflows/test-ruby.yml
index 117e751454c6db..07fd25fb1bffe5 100644
--- a/.github/workflows/test-ruby.yml
+++ b/.github/workflows/test-ruby.yml
@@ -48,12 +48,15 @@ jobs:
         run: |-
           ./bin/rails assets:precompile
 
+      - name: Archive asset artifacts
+        run: |
+          tar --exclude={"*.br","*.gz"} -zcf artifacts.tar.gz public/assets public/packs*
+
       - uses: actions/upload-artifact@v3
         if: matrix.mode == 'test'
         with:
           path: |-
-            ./public/assets
-            ./public/packs-test
+            ./artifacts.tar.gz
           name: ${{ github.sha }}
           retention-days: 0
 
@@ -102,7 +105,6 @@ jobs:
       SAML_ENABLED: true
       CAS_ENABLED: true
       BUNDLE_WITH: 'pam_authentication test'
-      CI_JOBS: ${{ matrix.ci_job }}/4
       GITHUB_RSPEC: ${{ matrix.ruby-version == '.ruby-version' && github.event.pull_request && 'true' }}
 
     strategy:
@@ -112,19 +114,18 @@ jobs:
           - '3.0'
           - '3.1'
           - '.ruby-version'
-        ci_job:
-          - 1
-          - 2
-          - 3
-          - 4
     steps:
       - uses: actions/checkout@v4
 
       - uses: actions/download-artifact@v3
         with:
-          path: './public'
+          path: './'
           name: ${{ github.sha }}
 
+      - name: Expand archived asset artifacts
+        run: |
+          tar xvzf artifacts.tar.gz
+
       - name: Set up Ruby environment
         uses: ./.github/actions/setup-ruby
         with:
@@ -134,7 +135,7 @@ jobs:
       - name: Load database schema
         run: './bin/rails db:create db:schema:load db:seed'
 
-      - run: bundle exec rake rspec_chunked
+      - run: bin/rspec
 
   test-e2e:
     name: End to End testing
diff --git a/.rubocop.yml b/.rubocop.yml
index 64ec766b223732..63de5e17c785f9 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -27,7 +27,7 @@ AllCops:
     - 'node_modules/**/*'
     - 'Vagrantfile'
     - 'vendor/**/*'
-    - 'lib/json_ld/*' # Generated files
+    - 'config/initializers/json_ld*' # Generated files
     - 'lib/mastodon/migration_helpers.rb' # Vendored from GitLab
     - 'lib/templates/**/*'
 
diff --git a/Gemfile b/Gemfile
index 1e84fff52d3654..2c355b416067df 100644
--- a/Gemfile
+++ b/Gemfile
@@ -88,7 +88,7 @@ gem 'simple-navigation', '~> 4.4'
 gem 'simple_form', '~> 5.2'
 gem 'sprockets-rails', '~> 3.4', require: 'sprockets/railtie'
 gem 'stoplight', '~> 3.0.1'
-gem 'strong_migrations', '~> 0.8'
+gem 'strong_migrations', '1.3.0'
 gem 'tty-prompt', '~> 0.23', require: false
 gem 'twitter-text', '~> 3.1.0'
 gem 'tzinfo-data', '~> 1.2023'
@@ -103,9 +103,6 @@ gem 'rdf-normalize', '~> 0.5'
 gem 'private_address_check', '~> 0.5'
 
 group :test do
-  # Used to split testing into chunks in CI
-  gem 'rspec_chunked', '~> 0.6'
-
   # Adds RSpec Error/Warning annotations to GitHub PRs on the Files tab
   gem 'rspec-github', '~> 2.4', require: false
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 8e1d7e43c4639d..c38666f91e32f4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -236,7 +236,7 @@ GEM
       devise (>= 4.0.0)
       rpam2 (~> 4.0)
     diff-lcs (1.5.0)
-    discard (1.2.1)
+    discard (1.3.0)
       activerecord (>= 4.2, < 8)
     docile (1.4.0)
     domain_name (0.5.20190701)
@@ -265,7 +265,7 @@ GEM
       tzinfo
     excon (0.100.0)
     fabrication (2.30.0)
-    faker (3.2.1)
+    faker (3.2.2)
       i18n (>= 1.8.11, < 2)
     faraday (1.10.3)
       faraday-em_http (~> 1.0)
@@ -536,7 +536,7 @@ GEM
     pundit (2.3.1)
       activesupport (>= 3.0.0)
     raabro (1.4.0)
-    racc (1.7.1)
+    racc (1.7.3)
     rack (2.2.8)
     rack-attack (6.7.0)
       rack (>= 1.0, < 4)
@@ -650,9 +650,7 @@ GEM
       rspec-mocks (~> 3.0)
       sidekiq (>= 5, < 8)
     rspec-support (3.12.1)
-    rspec_chunked (0.6)
-    rubocop (1.57.1)
-      base64 (~> 0.1.1)
+    rubocop (1.57.2)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
       parallel (~> 1.10)
@@ -742,7 +740,7 @@ GEM
     stoplight (3.0.2)
       redlock (~> 1.0)
     stringio (3.0.8)
-    strong_migrations (0.8.0)
+    strong_migrations (1.3.0)
       activerecord (>= 5.2)
     swd (1.3.0)
       activesupport (>= 3)
@@ -921,7 +919,6 @@ DEPENDENCIES
   rspec-github (~> 2.4)
   rspec-rails (~> 6.0)
   rspec-sidekiq (~> 4.0)
-  rspec_chunked (~> 0.6)
   rubocop
   rubocop-capybara
   rubocop-performance
@@ -944,7 +941,7 @@ DEPENDENCIES
   sprockets-rails (~> 3.4)
   stackprof
   stoplight (~> 3.0.1)
-  strong_migrations (~> 0.8)
+  strong_migrations (= 1.3.0)
   test-prof
   thor (~> 1.2)
   tty-prompt (~> 0.23)
diff --git a/SECURITY.md b/SECURITY.md
index 3e13377db63eb4..954ff73a247425 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -17,6 +17,6 @@ A "vulnerability in Mastodon" is a vulnerability in the code distributed through
 | ------- | ---------------- |
 | 4.2.x   | Yes              |
 | 4.1.x   | Yes              |
-| 4.0.x   | Until 2023-10-31 |
+| 4.0.x   | No               |
 | 3.5.x   | Until 2023-12-31 |
 | < 3.5   | No               |
diff --git a/app/javascript/flavours/glitch/components/autosuggest_textarea.jsx b/app/javascript/flavours/glitch/components/autosuggest_textarea.jsx
index c023b99f81bc7c..28384075c3c16e 100644
--- a/app/javascript/flavours/glitch/components/autosuggest_textarea.jsx
+++ b/app/javascript/flavours/glitch/components/autosuggest_textarea.jsx
@@ -1,9 +1,9 @@
 import PropTypes from 'prop-types';
+import { useCallback, useRef, useState, useEffect, forwardRef } from 'react';
 
 import classNames from 'classnames';
 
 import ImmutablePropTypes from 'react-immutable-proptypes';
-import ImmutablePureComponent from 'react-immutable-pure-component';
 
 import Textarea from 'react-textarea-autosize';
 
@@ -37,54 +37,46 @@ const textAtCursorMatchesToken = (str, caretPosition) => {
   }
 };
 
-export default class AutosuggestTextarea extends ImmutablePureComponent {
-
-  static propTypes = {
-    value: PropTypes.string,
-    suggestions: ImmutablePropTypes.list,
-    disabled: PropTypes.bool,
-    placeholder: PropTypes.string,
-    onSuggestionSelected: PropTypes.func.isRequired,
-    onSuggestionsClearRequested: PropTypes.func.isRequired,
-    onSuggestionsFetchRequested: PropTypes.func.isRequired,
-    onChange: PropTypes.func.isRequired,
-    onKeyUp: PropTypes.func,
-    onKeyDown: PropTypes.func,
-    onPaste: PropTypes.func.isRequired,
-    autoFocus: PropTypes.bool,
-    lang: PropTypes.string,
-  };
-
-  static defaultProps = {
-    autoFocus: true,
-  };
-
-  state = {
-    suggestionsHidden: true,
-    focused: false,
-    selectedSuggestion: 0,
-    lastToken: null,
-    tokenStart: 0,
-  };
-
-  onChange = (e) => {
+const AutosuggestTextarea = forwardRef(({
+  value,
+  suggestions,
+  disabled,
+  placeholder,
+  onSuggestionSelected,
+  onSuggestionsClearRequested,
+  onSuggestionsFetchRequested,
+  onChange,
+  onKeyUp,
+  onKeyDown,
+  onPaste,
+  onFocus,
+  autoFocus = true,
+  lang,
+  children,
+}, textareaRef) => {
+
+  const [suggestionsHidden, setSuggestionsHidden] = useState(true);
+  const [selectedSuggestion, setSelectedSuggestion] = useState(0);
+  const lastTokenRef = useRef(null);
+  const tokenStartRef = useRef(0);
+
+  const handleChange = useCallback((e) => {
     const [ tokenStart, token ] = textAtCursorMatchesToken(e.target.value, e.target.selectionStart);
 
-    if (token !== null && this.state.lastToken !== token) {
-      this.setState({ lastToken: token, selectedSuggestion: 0, tokenStart });
-      this.props.onSuggestionsFetchRequested(token);
+    if (token !== null && lastTokenRef.current !== token) {
+      tokenStartRef.current = tokenStart;
+      lastTokenRef.current = token;
+      setSelectedSuggestion(0);
+      onSuggestionsFetchRequested(token);
     } else if (token === null) {
-      this.setState({ lastToken: null });
-      this.props.onSuggestionsClearRequested();
+      lastTokenRef.current = null;
+      onSuggestionsClearRequested();
     }
 
-    this.props.onChange(e);
-  };
-
-  onKeyDown = (e) => {
-    const { suggestions, disabled } = this.props;
-    const { selectedSuggestion, suggestionsHidden } = this.state;
+    onChange(e);
+  }, [onSuggestionsFetchRequested, onSuggestionsClearRequested, onChange, setSelectedSuggestion]);
 
+  const handleKeyDown = useCallback((e) => {
     if (disabled) {
       e.preventDefault();
       return;
@@ -102,80 +94,75 @@ export default class AutosuggestTextarea extends ImmutablePureComponent {
         document.querySelector('.ui').parentElement.focus();
       } else {
         e.preventDefault();
-        this.setState({ suggestionsHidden: true });
+        setSuggestionsHidden(true);
       }
 
       break;
     case 'ArrowDown':
       if (suggestions.size > 0 && !suggestionsHidden) {
         e.preventDefault();
-        this.setState({ selectedSuggestion: Math.min(selectedSuggestion + 1, suggestions.size - 1) });
+        setSelectedSuggestion(Math.min(selectedSuggestion + 1, suggestions.size - 1));
       }
 
       break;
     case 'ArrowUp':
       if (suggestions.size > 0 && !suggestionsHidden) {
         e.preventDefault();
-        this.setState({ selectedSuggestion: Math.max(selectedSuggestion - 1, 0) });
+        setSelectedSuggestion(Math.max(selectedSuggestion - 1, 0));
       }
 
       break;
     case 'Enter':
     case 'Tab':
       // Select suggestion
-      if (this.state.lastToken !== null && suggestions.size > 0 && !suggestionsHidden) {
+      if (lastTokenRef.current !== null && suggestions.size > 0 && !suggestionsHidden) {
         e.preventDefault();
         e.stopPropagation();
-        this.props.onSuggestionSelected(this.state.tokenStart, this.state.lastToken, suggestions.get(selectedSuggestion));
+        onSuggestionSelected(tokenStartRef.current, lastTokenRef.current, suggestions.get(selectedSuggestion));
       }
 
       break;
     }
 
-    if (e.defaultPrevented || !this.props.onKeyDown) {
+    if (e.defaultPrevented || !onKeyDown) {
       return;
     }
 
-    this.props.onKeyDown(e);
-  };
+    onKeyDown(e);
+  }, [disabled, suggestions, suggestionsHidden, selectedSuggestion, setSelectedSuggestion, setSuggestionsHidden, onSuggestionSelected, onKeyDown]);
 
-  onBlur = () => {
-    this.setState({ suggestionsHidden: true, focused: false });
-  };
+  const handleBlur = useCallback(() => {
+    setSuggestionsHidden(true);
+  }, [setSuggestionsHidden]);
 
-  onFocus = (e) => {
-    this.setState({ focused: true });
-    if (this.props.onFocus) {
-      this.props.onFocus(e);
+  const handleFocus = useCallback((e) => {
+    if (onFocus) {
+      onFocus(e);
     }
-  };
+  }, [onFocus]);
 
-  onSuggestionClick = (e) => {
-    const suggestion = this.props.suggestions.get(e.currentTarget.getAttribute('data-index'));
+  const handleSuggestionClick = useCallback((e) => {
+    const suggestion = suggestions.get(e.currentTarget.getAttribute('data-index'));
     e.preventDefault();
-    this.props.onSuggestionSelected(this.state.tokenStart, this.state.lastToken, suggestion);
-    this.textarea.focus();
-  };
+    onSuggestionSelected(tokenStartRef.current, lastTokenRef.current, suggestion);
+    textareaRef.current?.focus();
+  }, [suggestions, onSuggestionSelected, textareaRef]);
 
-  UNSAFE_componentWillReceiveProps (nextProps) {
-    if (nextProps.suggestions !== this.props.suggestions && nextProps.suggestions.size > 0 && this.state.suggestionsHidden && this.state.focused) {
-      this.setState({ suggestionsHidden: false });
-    }
-  }
-
-  setTextarea = (c) => {
-    this.textarea = c;
-  };
-
-  onPaste = (e) => {
+  const handlePaste = useCallback((e) => {
     if (e.clipboardData && e.clipboardData.files.length === 1) {
-      this.props.onPaste(e.clipboardData.files);
+      onPaste(e.clipboardData.files);
       e.preventDefault();
     }
-  };
+  }, [onPaste]);
+
+  // Show the suggestions again whenever they change and the textarea is focused
+  useEffect(() => {
+    if (suggestions.size > 0 && textareaRef.current === document.activeElement) {
+      setSuggestionsHidden(false);
+    }
+  }, [suggestions, textareaRef, setSuggestionsHidden]);
 
-  renderSuggestion = (suggestion, i) => {
-    const { selectedSuggestion } = this.state;
+  const renderSuggestion = (suggestion, i) => {
     let inner, key;
 
     if (suggestion.type === 'emoji') {
@@ -190,50 +177,64 @@ export default class AutosuggestTextarea extends ImmutablePureComponent {
     }
 
     return (
-      <div role='button' tabIndex={0} key={key} data-index={i} className={classNames('autosuggest-textarea__suggestions__item', { selected: i === selectedSuggestion })} onMouseDown={this.onSuggestionClick}>
+      <div role='button' tabIndex={0} key={key} data-index={i} className={classNames('autosuggest-textarea__suggestions__item', { selected: i === selectedSuggestion })} onMouseDown={handleSuggestionClick}>
         {inner}
       </div>
     );
   };
 
-  render () {
-    const { value, suggestions, disabled, placeholder, onKeyUp, autoFocus, lang, children } = this.props;
-    const { suggestionsHidden } = this.state;
-
-    return [
-      <div className='compose-form__autosuggest-wrapper' key='autosuggest-wrapper'>
-        <div className='autosuggest-textarea'>
-          <label>
-            <span style={{ display: 'none' }}>{placeholder}</span>
-
-            <Textarea
-              ref={this.setTextarea}
-              className='autosuggest-textarea__textarea'
-              disabled={disabled}
-              placeholder={placeholder}
-              autoFocus={autoFocus}
-              value={value}
-              onChange={this.onChange}
-              onKeyDown={this.onKeyDown}
-              onKeyUp={onKeyUp}
-              onFocus={this.onFocus}
-              onBlur={this.onBlur}
-              onPaste={this.onPaste}
-              dir='auto'
-              aria-autocomplete='list'
-              lang={lang}
-            />
-          </label>
-        </div>
-        {children}
-      </div>,
-
-      <div className='autosuggest-textarea__suggestions-wrapper' key='suggestions-wrapper'>
-        <div className={`autosuggest-textarea__suggestions ${suggestionsHidden || suggestions.isEmpty() ? '' : 'autosuggest-textarea__suggestions--visible'}`}>
-          {suggestions.map(this.renderSuggestion)}
-        </div>
-      </div>,
-    ];
-  }
+  return [
+    <div className='compose-form__autosuggest-wrapper' key='autosuggest-wrapper'>
+      <div className='autosuggest-textarea'>
+        <label>
+          <span style={{ display: 'none' }}>{placeholder}</span>
+
+          <Textarea
+            ref={textareaRef}
+            className='autosuggest-textarea__textarea'
+            disabled={disabled}
+            placeholder={placeholder}
+            autoFocus={autoFocus}
+            value={value}
+            onChange={handleChange}
+            onKeyDown={handleKeyDown}
+            onKeyUp={onKeyUp}
+            onFocus={handleFocus}
+            onBlur={handleBlur}
+            onPaste={handlePaste}
+            dir='auto'
+            aria-autocomplete='list'
+            lang={lang}
+          />
+        </label>
+      </div>
+      {children}
+    </div>,
+
+    <div className='autosuggest-textarea__suggestions-wrapper' key='suggestions-wrapper'>
+      <div className={`autosuggest-textarea__suggestions ${suggestionsHidden || suggestions.isEmpty() ? '' : 'autosuggest-textarea__suggestions--visible'}`}>
+        {suggestions.map(renderSuggestion)}
+      </div>
+    </div>,
+  ];
+});
+
+AutosuggestTextarea.propTypes = {
+  value: PropTypes.string,
+  suggestions: ImmutablePropTypes.list,
+  disabled: PropTypes.bool,
+  placeholder: PropTypes.string,
+  onSuggestionSelected: PropTypes.func.isRequired,
+  onSuggestionsClearRequested: PropTypes.func.isRequired,
+  onSuggestionsFetchRequested: PropTypes.func.isRequired,
+  onChange: PropTypes.func.isRequired,
+  onKeyUp: PropTypes.func,
+  onKeyDown: PropTypes.func,
+  onPaste: PropTypes.func.isRequired,
+  onFocus:PropTypes.func,
+  children: PropTypes.node,
+  autoFocus: PropTypes.bool,
+  lang: PropTypes.string,
+};
 
-}
+export default AutosuggestTextarea;
diff --git a/app/javascript/flavours/glitch/features/compose/components/compose_form.jsx b/app/javascript/flavours/glitch/features/compose/components/compose_form.jsx
index c4cba922f5bb56..47b070da24290f 100644
--- a/app/javascript/flavours/glitch/features/compose/components/compose_form.jsx
+++ b/app/javascript/flavours/glitch/features/compose/components/compose_form.jsx
@@ -1,4 +1,5 @@
 import PropTypes from 'prop-types';
+import { createRef } from 'react';
 
 import { defineMessages, injectIntl } from 'react-intl';
 
@@ -90,6 +91,11 @@ class ComposeForm extends ImmutablePureComponent {
     highlighted: false,
   };
 
+  constructor(props) {
+    super(props);
+    this.textareaRef = createRef(null);
+  }
+
   handleChange = (e) => {
     this.props.onChange(e.target.value);
   };
@@ -118,10 +124,10 @@ class ComposeForm extends ImmutablePureComponent {
       onChangeVisibility,
     } = this.props;
 
-    if (this.props.text !== this.textarea.value) {
+    if (this.props.text !== this.textareaRef.current.value) {
       // Something changed the text inside the textarea (e.g. browser extensions like Grammarly)
       // Update the state to match the current text
-      this.props.onChange(this.textarea.value);
+      this.props.onChange(this.textareaRef.current.value);
     }
 
     if (!this.canSubmit()) {
@@ -154,10 +160,10 @@ class ComposeForm extends ImmutablePureComponent {
 
   //  Inserts an emoji at the caret.
   handleEmojiPick = (data) => {
-    const { textarea: { selectionStart } } = this;
-    const { onPickEmoji } = this.props;
-    if (onPickEmoji) {
-      onPickEmoji(selectionStart, data);
+    const position = this.textareaRef.current.selectionStart;
+
+    if (this.props.onPickEmoji) {
+      this.props.onPickEmoji(position, data);
     }
   };
 
@@ -188,13 +194,6 @@ class ComposeForm extends ImmutablePureComponent {
     }
   };
 
-  //  Sets a reference to the textarea.
-  setAutosuggestTextarea = (textareaComponent) => {
-    if (textareaComponent) {
-      this.textarea = textareaComponent.textarea;
-    }
-  };
-
   //  Sets a reference to the CW field.
   handleRefSpoilerText = (spoilerComponent) => {
     if (spoilerComponent) {
@@ -232,7 +231,6 @@ class ComposeForm extends ImmutablePureComponent {
   //        everyone else from the conversation.
   _updateFocusAndSelection = (prevProps) => {
     const {
-      textarea,
       spoilerText,
     } = this;
     const {
@@ -259,30 +257,30 @@ class ComposeForm extends ImmutablePureComponent {
       default:
         selectionStart = selectionEnd = text.length;
       }
-      if (textarea) {
+      if (this.textareaRef.current) {
         // Because of the wicg-inert polyfill, the activeElement may not be
         // immediately selectable, we have to wait for observers to run, as
         // described in https://github.com/WICG/inert#performance-and-gotchas
         Promise.resolve().then(() => {
-          textarea.setSelectionRange(selectionStart, selectionEnd);
-          textarea.focus();
-          if (!singleColumn) textarea.scrollIntoView();
+          this.textareaRef.current.setSelectionRange(selectionStart, selectionEnd);
+          this.textareaRef.current.focus();
+          if (!singleColumn) this.textareaRef.current.scrollIntoView();
           this.setState({ highlighted: true });
           this.timeout = setTimeout(() => this.setState({ highlighted: false }), 700);
         }).catch(console.error);
       }
 
     //  Refocuses the textarea after submitting.
-    } else if (textarea && prevProps.isSubmitting && !isSubmitting) {
-      textarea.focus();
+    } else if (this.textareaRef.current && prevProps.isSubmitting && !isSubmitting) {
+      this.textareaRef.current.focus();
     } else if (this.props.spoiler !== prevProps.spoiler) {
       if (this.props.spoiler) {
         if (spoilerText) {
           spoilerText.focus();
         }
       } else {
-        if (textarea) {
-          textarea.focus();
+        if (this.textareaRef.current) {
+          this.textareaRef.current.focus();
         }
       }
     }
@@ -347,7 +345,7 @@ class ComposeForm extends ImmutablePureComponent {
 
         <div className={classNames('compose-form__highlightable', { active: highlighted })}>
           <AutosuggestTextarea
-            ref={this.setAutosuggestTextarea}
+            ref={this.textareaRef}
             placeholder={intl.formatMessage(messages.placeholder)}
             disabled={isSubmitting}
             value={this.props.text}
diff --git a/app/javascript/flavours/glitch/polyfills/base_polyfills.ts b/app/javascript/flavours/glitch/polyfills/base_polyfills.ts
deleted file mode 100644
index 71565236cd00c3..00000000000000
--- a/app/javascript/flavours/glitch/polyfills/base_polyfills.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-import 'core-js/features/object/assign';
-import 'core-js/features/object/values';
-import 'core-js/features/symbol';
-import 'core-js/features/promise/finally';
-import { decode as decodeBase64 } from '../utils/base64';
-
-if (!Object.hasOwn(HTMLCanvasElement.prototype, 'toBlob')) {
-  const BASE64_MARKER = ';base64,';
-
-  Object.defineProperty(HTMLCanvasElement.prototype, 'toBlob', {
-    value: function (
-      this: HTMLCanvasElement,
-      callback: BlobCallback,
-      type = 'image/png',
-      quality: unknown,
-    ) {
-      const dataURL: string = this.toDataURL(type, quality);
-      let data;
-
-      if (dataURL.includes(BASE64_MARKER)) {
-        const [, base64] = dataURL.split(BASE64_MARKER);
-        data = decodeBase64(base64);
-      } else {
-        [, data] = dataURL.split(',');
-      }
-
-      callback(new Blob([data], { type }));
-    },
-  });
-}
diff --git a/app/javascript/flavours/glitch/polyfills/extra_polyfills.ts b/app/javascript/flavours/glitch/polyfills/extra_polyfills.ts
index e6c69de8b557b7..a8d5530c5fcb6a 100644
--- a/app/javascript/flavours/glitch/polyfills/extra_polyfills.ts
+++ b/app/javascript/flavours/glitch/polyfills/extra_polyfills.ts
@@ -1,2 +1 @@
-import 'abortcontroller-polyfill/dist/abortcontroller-polyfill-only';
 import 'requestidlecallback';
diff --git a/app/javascript/flavours/glitch/polyfills/index.ts b/app/javascript/flavours/glitch/polyfills/index.ts
index e166c09d0e8b23..431c5b0f30f350 100644
--- a/app/javascript/flavours/glitch/polyfills/index.ts
+++ b/app/javascript/flavours/glitch/polyfills/index.ts
@@ -4,39 +4,18 @@
 
 import { loadIntlPolyfills } from './intl';
 
-function importBasePolyfills() {
-  return import(/* webpackChunkName: "base_polyfills" */ './base_polyfills');
-}
-
 function importExtraPolyfills() {
   return import(/* webpackChunkName: "extra_polyfills" */ './extra_polyfills');
 }
 
 export function loadPolyfills() {
-  const needsBasePolyfills = !(
-    'toBlob' in HTMLCanvasElement.prototype &&
-    'assign' in Object &&
-    'values' in Object &&
-    'Symbol' in window &&
-    'finally' in Promise.prototype
-  );
-
-  // Latest version of Firefox and Safari do not have IntersectionObserver.
-  // Edge does not have requestIdleCallback.
+  // Safari does not have requestIdleCallback.
   // This avoids shipping them all the polyfills.
-  /* eslint-disable @typescript-eslint/no-unnecessary-condition -- those properties might not exist in old browsers, even if they are always here in types */
-  const needsExtraPolyfills = !(
-    window.AbortController &&
-    window.IntersectionObserver &&
-    window.IntersectionObserverEntry &&
-    'isIntersecting' in IntersectionObserverEntry.prototype &&
-    window.requestIdleCallback
-  );
-  /* eslint-enable @typescript-eslint/no-unnecessary-condition */
+  const needsExtraPolyfills = !window.requestIdleCallback;
 
   return Promise.all([
     loadIntlPolyfills(),
-    needsBasePolyfills && importBasePolyfills(),
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition -- those properties might not exist in old browsers, even if they are always here in types
     needsExtraPolyfills && importExtraPolyfills(),
   ]);
 }
diff --git a/app/javascript/mastodon/actions/account_notes.ts b/app/javascript/mastodon/actions/account_notes.ts
index eeef23e3666c50..e524e5235bfe5a 100644
--- a/app/javascript/mastodon/actions/account_notes.ts
+++ b/app/javascript/mastodon/actions/account_notes.ts
@@ -1,3 +1,4 @@
+import type { ApiRelationshipJSON } from 'mastodon/api_types/relationships';
 import { createAppAsyncThunk } from 'mastodon/store/typed_functions';
 
 import api from '../api';
@@ -5,8 +6,7 @@ import api from '../api';
 export const submitAccountNote = createAppAsyncThunk(
   'account_note/submit',
   async (args: { id: string; value: string }, { getState }) => {
-    // TODO: replace `unknown` with `ApiRelationshipJSON` when it is merged
-    const response = await api(getState).post<unknown>(
+    const response = await api(getState).post<ApiRelationshipJSON>(
       `/api/v1/accounts/${args.id}/note`,
       {
         comment: args.value,
diff --git a/app/javascript/mastodon/actions/accounts.js b/app/javascript/mastodon/actions/accounts.js
index 3a85393d6cf273..4a985a41eff0f3 100644
--- a/app/javascript/mastodon/actions/accounts.js
+++ b/app/javascript/mastodon/actions/accounts.js
@@ -1,5 +1,15 @@
 import api, { getLinks } from '../api';
 
+import {
+  followAccountSuccess, unfollowAccountSuccess,
+  authorizeFollowRequestSuccess, rejectFollowRequestSuccess,
+  followAccountRequest, followAccountFail,
+  unfollowAccountRequest, unfollowAccountFail,
+  muteAccountSuccess, unmuteAccountSuccess,
+  blockAccountSuccess, unblockAccountSuccess,
+  pinAccountSuccess, unpinAccountSuccess,
+  fetchRelationshipsSuccess,
+} from './accounts_typed';
 import { importFetchedAccount, importFetchedAccounts } from './importer';
 
 export const ACCOUNT_FETCH_REQUEST = 'ACCOUNT_FETCH_REQUEST';
@@ -10,36 +20,22 @@ export const ACCOUNT_LOOKUP_REQUEST = 'ACCOUNT_LOOKUP_REQUEST';
 export const ACCOUNT_LOOKUP_SUCCESS = 'ACCOUNT_LOOKUP_SUCCESS';
 export const ACCOUNT_LOOKUP_FAIL    = 'ACCOUNT_LOOKUP_FAIL';
 
-export const ACCOUNT_FOLLOW_REQUEST = 'ACCOUNT_FOLLOW_REQUEST';
-export const ACCOUNT_FOLLOW_SUCCESS = 'ACCOUNT_FOLLOW_SUCCESS';
-export const ACCOUNT_FOLLOW_FAIL    = 'ACCOUNT_FOLLOW_FAIL';
-
-export const ACCOUNT_UNFOLLOW_REQUEST = 'ACCOUNT_UNFOLLOW_REQUEST';
-export const ACCOUNT_UNFOLLOW_SUCCESS = 'ACCOUNT_UNFOLLOW_SUCCESS';
-export const ACCOUNT_UNFOLLOW_FAIL    = 'ACCOUNT_UNFOLLOW_FAIL';
-
 export const ACCOUNT_BLOCK_REQUEST = 'ACCOUNT_BLOCK_REQUEST';
-export const ACCOUNT_BLOCK_SUCCESS = 'ACCOUNT_BLOCK_SUCCESS';
 export const ACCOUNT_BLOCK_FAIL    = 'ACCOUNT_BLOCK_FAIL';
 
 export const ACCOUNT_UNBLOCK_REQUEST = 'ACCOUNT_UNBLOCK_REQUEST';
-export const ACCOUNT_UNBLOCK_SUCCESS = 'ACCOUNT_UNBLOCK_SUCCESS';
 export const ACCOUNT_UNBLOCK_FAIL    = 'ACCOUNT_UNBLOCK_FAIL';
 
 export const ACCOUNT_MUTE_REQUEST = 'ACCOUNT_MUTE_REQUEST';
-export const ACCOUNT_MUTE_SUCCESS = 'ACCOUNT_MUTE_SUCCESS';
 export const ACCOUNT_MUTE_FAIL    = 'ACCOUNT_MUTE_FAIL';
 
 export const ACCOUNT_UNMUTE_REQUEST = 'ACCOUNT_UNMUTE_REQUEST';
-export const ACCOUNT_UNMUTE_SUCCESS = 'ACCOUNT_UNMUTE_SUCCESS';
 export const ACCOUNT_UNMUTE_FAIL    = 'ACCOUNT_UNMUTE_FAIL';
 
 export const ACCOUNT_PIN_REQUEST = 'ACCOUNT_PIN_REQUEST';
-export const ACCOUNT_PIN_SUCCESS = 'ACCOUNT_PIN_SUCCESS';
 export const ACCOUNT_PIN_FAIL    = 'ACCOUNT_PIN_FAIL';
 
 export const ACCOUNT_UNPIN_REQUEST = 'ACCOUNT_UNPIN_REQUEST';
-export const ACCOUNT_UNPIN_SUCCESS = 'ACCOUNT_UNPIN_SUCCESS';
 export const ACCOUNT_UNPIN_FAIL    = 'ACCOUNT_UNPIN_FAIL';
 
 export const FOLLOWERS_FETCH_REQUEST = 'FOLLOWERS_FETCH_REQUEST';
@@ -59,7 +55,6 @@ export const FOLLOWING_EXPAND_SUCCESS = 'FOLLOWING_EXPAND_SUCCESS';
 export const FOLLOWING_EXPAND_FAIL    = 'FOLLOWING_EXPAND_FAIL';
 
 export const RELATIONSHIPS_FETCH_REQUEST = 'RELATIONSHIPS_FETCH_REQUEST';
-export const RELATIONSHIPS_FETCH_SUCCESS = 'RELATIONSHIPS_FETCH_SUCCESS';
 export const RELATIONSHIPS_FETCH_FAIL    = 'RELATIONSHIPS_FETCH_FAIL';
 
 export const FOLLOW_REQUESTS_FETCH_REQUEST = 'FOLLOW_REQUESTS_FETCH_REQUEST';
@@ -71,15 +66,15 @@ export const FOLLOW_REQUESTS_EXPAND_SUCCESS = 'FOLLOW_REQUESTS_EXPAND_SUCCESS';
 export const FOLLOW_REQUESTS_EXPAND_FAIL    = 'FOLLOW_REQUESTS_EXPAND_FAIL';
 
 export const FOLLOW_REQUEST_AUTHORIZE_REQUEST = 'FOLLOW_REQUEST_AUTHORIZE_REQUEST';
-export const FOLLOW_REQUEST_AUTHORIZE_SUCCESS = 'FOLLOW_REQUEST_AUTHORIZE_SUCCESS';
 export const FOLLOW_REQUEST_AUTHORIZE_FAIL    = 'FOLLOW_REQUEST_AUTHORIZE_FAIL';
 
 export const FOLLOW_REQUEST_REJECT_REQUEST = 'FOLLOW_REQUEST_REJECT_REQUEST';
-export const FOLLOW_REQUEST_REJECT_SUCCESS = 'FOLLOW_REQUEST_REJECT_SUCCESS';
 export const FOLLOW_REQUEST_REJECT_FAIL    = 'FOLLOW_REQUEST_REJECT_FAIL';
 
 export const ACCOUNT_REVEAL = 'ACCOUNT_REVEAL';
 
+export * from './accounts_typed';
+
 export function fetchAccount(id) {
   return (dispatch, getState) => {
     dispatch(fetchRelationships([id]));
@@ -149,12 +144,12 @@ export function followAccount(id, options = { reblogs: true }) {
     const alreadyFollowing = getState().getIn(['relationships', id, 'following']);
     const locked = getState().getIn(['accounts', id, 'locked'], false);
 
-    dispatch(followAccountRequest(id, locked));
+    dispatch(followAccountRequest({ id, locked }));
 
     api(getState).post(`/api/v1/accounts/${id}/follow`, options).then(response => {
-      dispatch(followAccountSuccess(response.data, alreadyFollowing));
+      dispatch(followAccountSuccess({relationship: response.data, alreadyFollowing}));
     }).catch(error => {
-      dispatch(followAccountFail(error, locked));
+      dispatch(followAccountFail({ id, error, locked }));
     });
   };
 }
@@ -164,74 +159,22 @@ export function unfollowAccount(id) {
     dispatch(unfollowAccountRequest(id));
 
     api(getState).post(`/api/v1/accounts/${id}/unfollow`).then(response => {
-      dispatch(unfollowAccountSuccess(response.data, getState().get('statuses')));
+      dispatch(unfollowAccountSuccess({relationship: response.data, statuses: getState().get('statuses')}));
     }).catch(error => {
-      dispatch(unfollowAccountFail(error));
+      dispatch(unfollowAccountFail({ id, error }));
     });
   };
 }
 
-export function followAccountRequest(id, locked) {
-  return {
-    type: ACCOUNT_FOLLOW_REQUEST,
-    id,
-    locked,
-    skipLoading: true,
-  };
-}
-
-export function followAccountSuccess(relationship, alreadyFollowing) {
-  return {
-    type: ACCOUNT_FOLLOW_SUCCESS,
-    relationship,
-    alreadyFollowing,
-    skipLoading: true,
-  };
-}
-
-export function followAccountFail(error, locked) {
-  return {
-    type: ACCOUNT_FOLLOW_FAIL,
-    error,
-    locked,
-    skipLoading: true,
-  };
-}
-
-export function unfollowAccountRequest(id) {
-  return {
-    type: ACCOUNT_UNFOLLOW_REQUEST,
-    id,
-    skipLoading: true,
-  };
-}
-
-export function unfollowAccountSuccess(relationship, statuses) {
-  return {
-    type: ACCOUNT_UNFOLLOW_SUCCESS,
-    relationship,
-    statuses,
-    skipLoading: true,
-  };
-}
-
-export function unfollowAccountFail(error) {
-  return {
-    type: ACCOUNT_UNFOLLOW_FAIL,
-    error,
-    skipLoading: true,
-  };
-}
-
 export function blockAccount(id) {
   return (dispatch, getState) => {
     dispatch(blockAccountRequest(id));
 
     api(getState).post(`/api/v1/accounts/${id}/block`).then(response => {
       // Pass in entire statuses map so we can use it to filter stuff in different parts of the reducers
-      dispatch(blockAccountSuccess(response.data, getState().get('statuses')));
+      dispatch(blockAccountSuccess({ relationship: response.data, statuses: getState().get('statuses') }));
     }).catch(error => {
-      dispatch(blockAccountFail(id, error));
+      dispatch(blockAccountFail({ id, error }));
     });
   };
 }
@@ -241,9 +184,9 @@ export function unblockAccount(id) {
     dispatch(unblockAccountRequest(id));
 
     api(getState).post(`/api/v1/accounts/${id}/unblock`).then(response => {
-      dispatch(unblockAccountSuccess(response.data));
+      dispatch(unblockAccountSuccess({ relationship: response.data }));
     }).catch(error => {
-      dispatch(unblockAccountFail(id, error));
+      dispatch(unblockAccountFail({ id, error }));
     });
   };
 }
@@ -254,15 +197,6 @@ export function blockAccountRequest(id) {
     id,
   };
 }
-
-export function blockAccountSuccess(relationship, statuses) {
-  return {
-    type: ACCOUNT_BLOCK_SUCCESS,
-    relationship,
-    statuses,
-  };
-}
-
 export function blockAccountFail(error) {
   return {
     type: ACCOUNT_BLOCK_FAIL,
@@ -277,13 +211,6 @@ export function unblockAccountRequest(id) {
   };
 }
 
-export function unblockAccountSuccess(relationship) {
-  return {
-    type: ACCOUNT_UNBLOCK_SUCCESS,
-    relationship,
-  };
-}
-
 export function unblockAccountFail(error) {
   return {
     type: ACCOUNT_UNBLOCK_FAIL,
@@ -298,9 +225,9 @@ export function muteAccount(id, notifications, duration=0) {
 
     api(getState).post(`/api/v1/accounts/${id}/mute`, { notifications, duration }).then(response => {
       // Pass in entire statuses map so we can use it to filter stuff in different parts of the reducers
-      dispatch(muteAccountSuccess(response.data, getState().get('statuses')));
+      dispatch(muteAccountSuccess({ relationship: response.data, statuses: getState().get('statuses') }));
     }).catch(error => {
-      dispatch(muteAccountFail(id, error));
+      dispatch(muteAccountFail({ id, error }));
     });
   };
 }
@@ -310,9 +237,9 @@ export function unmuteAccount(id) {
     dispatch(unmuteAccountRequest(id));
 
     api(getState).post(`/api/v1/accounts/${id}/unmute`).then(response => {
-      dispatch(unmuteAccountSuccess(response.data));
+      dispatch(unmuteAccountSuccess({ relationship: response.data }));
     }).catch(error => {
-      dispatch(unmuteAccountFail(id, error));
+      dispatch(unmuteAccountFail({ id, error }));
     });
   };
 }
@@ -324,14 +251,6 @@ export function muteAccountRequest(id) {
   };
 }
 
-export function muteAccountSuccess(relationship, statuses) {
-  return {
-    type: ACCOUNT_MUTE_SUCCESS,
-    relationship,
-    statuses,
-  };
-}
-
 export function muteAccountFail(error) {
   return {
     type: ACCOUNT_MUTE_FAIL,
@@ -346,13 +265,6 @@ export function unmuteAccountRequest(id) {
   };
 }
 
-export function unmuteAccountSuccess(relationship) {
-  return {
-    type: ACCOUNT_UNMUTE_SUCCESS,
-    relationship,
-  };
-}
-
 export function unmuteAccountFail(error) {
   return {
     type: ACCOUNT_UNMUTE_FAIL,
@@ -549,7 +461,7 @@ export function fetchRelationships(accountIds) {
     dispatch(fetchRelationshipsRequest(newAccountIds));
 
     api(getState).get(`/api/v1/accounts/relationships?${newAccountIds.map(id => `id[]=${id}`).join('&')}`).then(response => {
-      dispatch(fetchRelationshipsSuccess(response.data));
+      dispatch(fetchRelationshipsSuccess({ relationships: response.data }));
     }).catch(error => {
       dispatch(fetchRelationshipsFail(error));
     });
@@ -564,14 +476,6 @@ export function fetchRelationshipsRequest(ids) {
   };
 }
 
-export function fetchRelationshipsSuccess(relationships) {
-  return {
-    type: RELATIONSHIPS_FETCH_SUCCESS,
-    relationships,
-    skipLoading: true,
-  };
-}
-
 export function fetchRelationshipsFail(error) {
   return {
     type: RELATIONSHIPS_FETCH_FAIL,
@@ -659,7 +563,7 @@ export function authorizeFollowRequest(id) {
 
     api(getState)
       .post(`/api/v1/follow_requests/${id}/authorize`)
-      .then(() => dispatch(authorizeFollowRequestSuccess(id)))
+      .then(() => dispatch(authorizeFollowRequestSuccess({ id })))
       .catch(error => dispatch(authorizeFollowRequestFail(id, error)));
   };
 }
@@ -671,13 +575,6 @@ export function authorizeFollowRequestRequest(id) {
   };
 }
 
-export function authorizeFollowRequestSuccess(id) {
-  return {
-    type: FOLLOW_REQUEST_AUTHORIZE_SUCCESS,
-    id,
-  };
-}
-
 export function authorizeFollowRequestFail(id, error) {
   return {
     type: FOLLOW_REQUEST_AUTHORIZE_FAIL,
@@ -693,7 +590,7 @@ export function rejectFollowRequest(id) {
 
     api(getState)
       .post(`/api/v1/follow_requests/${id}/reject`)
-      .then(() => dispatch(rejectFollowRequestSuccess(id)))
+      .then(() => dispatch(rejectFollowRequestSuccess({ id })))
       .catch(error => dispatch(rejectFollowRequestFail(id, error)));
   };
 }
@@ -705,13 +602,6 @@ export function rejectFollowRequestRequest(id) {
   };
 }
 
-export function rejectFollowRequestSuccess(id) {
-  return {
-    type: FOLLOW_REQUEST_REJECT_SUCCESS,
-    id,
-  };
-}
-
 export function rejectFollowRequestFail(id, error) {
   return {
     type: FOLLOW_REQUEST_REJECT_FAIL,
@@ -725,7 +615,7 @@ export function pinAccount(id) {
     dispatch(pinAccountRequest(id));
 
     api(getState).post(`/api/v1/accounts/${id}/pin`).then(response => {
-      dispatch(pinAccountSuccess(response.data));
+      dispatch(pinAccountSuccess({ relationship: response.data }));
     }).catch(error => {
       dispatch(pinAccountFail(error));
     });
@@ -737,7 +627,7 @@ export function unpinAccount(id) {
     dispatch(unpinAccountRequest(id));
 
     api(getState).post(`/api/v1/accounts/${id}/unpin`).then(response => {
-      dispatch(unpinAccountSuccess(response.data));
+      dispatch(unpinAccountSuccess({ relationship: response.data }));
     }).catch(error => {
       dispatch(unpinAccountFail(error));
     });
@@ -751,13 +641,6 @@ export function pinAccountRequest(id) {
   };
 }
 
-export function pinAccountSuccess(relationship) {
-  return {
-    type: ACCOUNT_PIN_SUCCESS,
-    relationship,
-  };
-}
-
 export function pinAccountFail(error) {
   return {
     type: ACCOUNT_PIN_FAIL,
@@ -772,21 +655,9 @@ export function unpinAccountRequest(id) {
   };
 }
 
-export function unpinAccountSuccess(relationship) {
-  return {
-    type: ACCOUNT_UNPIN_SUCCESS,
-    relationship,
-  };
-}
-
 export function unpinAccountFail(error) {
   return {
     type: ACCOUNT_UNPIN_FAIL,
     error,
   };
 }
-
-export const revealAccount = id => ({
-  type: ACCOUNT_REVEAL,
-  id,
-});
diff --git a/app/javascript/mastodon/actions/accounts_typed.ts b/app/javascript/mastodon/actions/accounts_typed.ts
new file mode 100644
index 00000000000000..b908e7528eeb60
--- /dev/null
+++ b/app/javascript/mastodon/actions/accounts_typed.ts
@@ -0,0 +1,97 @@
+import { createAction } from '@reduxjs/toolkit';
+
+import type { ApiAccountJSON } from 'mastodon/api_types/accounts';
+import type { ApiRelationshipJSON } from 'mastodon/api_types/relationships';
+
+export const revealAccount = createAction<{
+  id: string;
+}>('accounts/revealAccount');
+
+export const importAccounts = createAction<{ accounts: ApiAccountJSON[] }>(
+  'accounts/importAccounts',
+);
+
+function actionWithSkipLoadingTrue<Args extends object>(args: Args) {
+  return {
+    payload: {
+      ...args,
+      skipLoading: true,
+    },
+  };
+}
+
+export const followAccountSuccess = createAction(
+  'accounts/followAccountSuccess',
+  actionWithSkipLoadingTrue<{
+    relationship: ApiRelationshipJSON;
+    alreadyFollowing: boolean;
+  }>,
+);
+
+export const unfollowAccountSuccess = createAction(
+  'accounts/unfollowAccountSuccess',
+  actionWithSkipLoadingTrue<{
+    relationship: ApiRelationshipJSON;
+    statuses: unknown;
+    alreadyFollowing?: boolean;
+  }>,
+);
+
+export const authorizeFollowRequestSuccess = createAction<{ id: string }>(
+  'accounts/followRequestAuthorizeSuccess',
+);
+
+export const rejectFollowRequestSuccess = createAction<{ id: string }>(
+  'accounts/followRequestRejectSuccess',
+);
+
+export const followAccountRequest = createAction(
+  'accounts/followRequest',
+  actionWithSkipLoadingTrue<{ id: string; locked: boolean }>,
+);
+
+export const followAccountFail = createAction(
+  'accounts/followFail',
+  actionWithSkipLoadingTrue<{ id: string; error: string; locked: boolean }>,
+);
+
+export const unfollowAccountRequest = createAction(
+  'accounts/unfollowRequest',
+  actionWithSkipLoadingTrue<{ id: string }>,
+);
+
+export const unfollowAccountFail = createAction(
+  'accounts/unfollowFail',
+  actionWithSkipLoadingTrue<{ id: string; error: string }>,
+);
+
+export const blockAccountSuccess = createAction<{
+  relationship: ApiRelationshipJSON;
+  statuses: unknown;
+}>('accounts/blockSuccess');
+
+export const unblockAccountSuccess = createAction<{
+  relationship: ApiRelationshipJSON;
+}>('accounts/unblockSuccess');
+
+export const muteAccountSuccess = createAction<{
+  relationship: ApiRelationshipJSON;
+  statuses: unknown;
+}>('accounts/muteSuccess');
+
+export const unmuteAccountSuccess = createAction<{
+  relationship: ApiRelationshipJSON;
+}>('accounts/unmuteSuccess');
+
+export const pinAccountSuccess = createAction<{
+  relationship: ApiRelationshipJSON;
+}>('accounts/pinSuccess');
+
+export const unpinAccountSuccess = createAction<{
+  relationship: ApiRelationshipJSON;
+}>('accounts/unpinSuccess');
+
+export const fetchRelationshipsSuccess = createAction(
+  'relationships/fetchSuccess',
+  actionWithSkipLoadingTrue<{ relationships: ApiRelationshipJSON[] }>,
+);
diff --git a/app/javascript/mastodon/actions/domain_blocks.js b/app/javascript/mastodon/actions/domain_blocks.js
index d06de20a2d17f5..718002613f4053 100644
--- a/app/javascript/mastodon/actions/domain_blocks.js
+++ b/app/javascript/mastodon/actions/domain_blocks.js
@@ -1,11 +1,13 @@
 import api, { getLinks } from '../api';
 
+import { blockDomainSuccess, unblockDomainSuccess } from "./domain_blocks_typed";
+
+export * from "./domain_blocks_typed";
+
 export const DOMAIN_BLOCK_REQUEST = 'DOMAIN_BLOCK_REQUEST';
-export const DOMAIN_BLOCK_SUCCESS = 'DOMAIN_BLOCK_SUCCESS';
 export const DOMAIN_BLOCK_FAIL    = 'DOMAIN_BLOCK_FAIL';
 
 export const DOMAIN_UNBLOCK_REQUEST = 'DOMAIN_UNBLOCK_REQUEST';
-export const DOMAIN_UNBLOCK_SUCCESS = 'DOMAIN_UNBLOCK_SUCCESS';
 export const DOMAIN_UNBLOCK_FAIL    = 'DOMAIN_UNBLOCK_FAIL';
 
 export const DOMAIN_BLOCKS_FETCH_REQUEST = 'DOMAIN_BLOCKS_FETCH_REQUEST';
@@ -24,7 +26,7 @@ export function blockDomain(domain) {
       const at_domain = '@' + domain;
       const accounts = getState().get('accounts').filter(item => item.get('acct').endsWith(at_domain)).valueSeq().map(item => item.get('id'));
 
-      dispatch(blockDomainSuccess(domain, accounts));
+      dispatch(blockDomainSuccess({ domain, accounts }));
     }).catch(err => {
       dispatch(blockDomainFail(domain, err));
     });
@@ -38,14 +40,6 @@ export function blockDomainRequest(domain) {
   };
 }
 
-export function blockDomainSuccess(domain, accounts) {
-  return {
-    type: DOMAIN_BLOCK_SUCCESS,
-    domain,
-    accounts,
-  };
-}
-
 export function blockDomainFail(domain, error) {
   return {
     type: DOMAIN_BLOCK_FAIL,
@@ -61,7 +55,7 @@ export function unblockDomain(domain) {
     api(getState).delete('/api/v1/domain_blocks', { params: { domain } }).then(() => {
       const at_domain = '@' + domain;
       const accounts = getState().get('accounts').filter(item => item.get('acct').endsWith(at_domain)).valueSeq().map(item => item.get('id'));
-      dispatch(unblockDomainSuccess(domain, accounts));
+      dispatch(unblockDomainSuccess({ domain, accounts }));
     }).catch(err => {
       dispatch(unblockDomainFail(domain, err));
     });
@@ -75,14 +69,6 @@ export function unblockDomainRequest(domain) {
   };
 }
 
-export function unblockDomainSuccess(domain, accounts) {
-  return {
-    type: DOMAIN_UNBLOCK_SUCCESS,
-    domain,
-    accounts,
-  };
-}
-
 export function unblockDomainFail(domain, error) {
   return {
     type: DOMAIN_UNBLOCK_FAIL,
diff --git a/app/javascript/mastodon/actions/domain_blocks_typed.ts b/app/javascript/mastodon/actions/domain_blocks_typed.ts
new file mode 100644
index 00000000000000..08e0b4a1788e60
--- /dev/null
+++ b/app/javascript/mastodon/actions/domain_blocks_typed.ts
@@ -0,0 +1,13 @@
+import { createAction } from '@reduxjs/toolkit';
+
+import type { Account } from 'mastodon/models/account';
+
+export const blockDomainSuccess = createAction<{
+  domain: string;
+  accounts: Account[];
+}>('domain_blocks/blockSuccess');
+
+export const unblockDomainSuccess = createAction<{
+  domain: string;
+  accounts: Account[];
+}>('domain_blocks/unblockSuccess');
diff --git a/app/javascript/mastodon/actions/importer/index.js b/app/javascript/mastodon/actions/importer/index.js
index 369be6b8fbc0ca..16f191b5846f63 100644
--- a/app/javascript/mastodon/actions/importer/index.js
+++ b/app/javascript/mastodon/actions/importer/index.js
@@ -1,7 +1,7 @@
-import { normalizeAccount, normalizeStatus, normalizePoll } from './normalizer';
+import { importAccounts } from '../accounts_typed';
+
+import { normalizeStatus, normalizePoll } from './normalizer';
 
-export const ACCOUNT_IMPORT  = 'ACCOUNT_IMPORT';
-export const ACCOUNTS_IMPORT = 'ACCOUNTS_IMPORT';
 export const STATUS_IMPORT   = 'STATUS_IMPORT';
 export const STATUSES_IMPORT = 'STATUSES_IMPORT';
 export const POLLS_IMPORT    = 'POLLS_IMPORT';
@@ -13,14 +13,6 @@ function pushUnique(array, object) {
   }
 }
 
-export function importAccount(account) {
-  return { type: ACCOUNT_IMPORT, account };
-}
-
-export function importAccounts(accounts) {
-  return { type: ACCOUNTS_IMPORT, accounts };
-}
-
 export function importStatus(status) {
   return { type: STATUS_IMPORT, status };
 }
@@ -45,7 +37,7 @@ export function importFetchedAccounts(accounts) {
   const normalAccounts = [];
 
   function processAccount(account) {
-    pushUnique(normalAccounts, normalizeAccount(account));
+    pushUnique(normalAccounts, account);
 
     if (account.moved) {
       processAccount(account.moved);
@@ -54,7 +46,7 @@ export function importFetchedAccounts(accounts) {
 
   accounts.forEach(processAccount);
 
-  return importAccounts(normalAccounts);
+  return importAccounts({ accounts: normalAccounts });
 }
 
 export function importFetchedStatus(status) {
diff --git a/app/javascript/mastodon/actions/importer/normalizer.js b/app/javascript/mastodon/actions/importer/normalizer.js
index a72142a86f70bb..b5a30343e488c4 100644
--- a/app/javascript/mastodon/actions/importer/normalizer.js
+++ b/app/javascript/mastodon/actions/importer/normalizer.js
@@ -2,7 +2,6 @@ import escapeTextContentForBrowser from 'escape-html';
 
 import emojify from '../../features/emoji/emoji';
 import { expandSpoilers } from '../../initial_state';
-import { unescapeHTML } from '../../utils/html';
 
 const domParser = new DOMParser();
 
@@ -17,32 +16,6 @@ export function searchTextFromRawStatus (status) {
   return domParser.parseFromString(searchContent, 'text/html').documentElement.textContent;
 }
 
-export function normalizeAccount(account) {
-  account = { ...account };
-
-  const emojiMap = makeEmojiMap(account.emojis);
-  const displayName = account.display_name.trim().length === 0 ? account.username : account.display_name;
-
-  account.display_name_html = emojify(escapeTextContentForBrowser(displayName), emojiMap);
-  account.note_emojified = emojify(account.note, emojiMap);
-  account.note_plain = unescapeHTML(account.note);
-
-  if (account.fields) {
-    account.fields = account.fields.map(pair => ({
-      ...pair,
-      name_emojified: emojify(escapeTextContentForBrowser(pair.name), emojiMap),
-      value_emojified: emojify(pair.value, emojiMap),
-      value_plain: unescapeHTML(pair.value),
-    }));
-  }
-
-  if (account.moved) {
-    account.moved = account.moved.id;
-  }
-
-  return account;
-}
-
 export function normalizeFilterResult(result) {
   const normalResult = { ...result };
 
diff --git a/app/javascript/mastodon/actions/notifications.js b/app/javascript/mastodon/actions/notifications.js
index 02fe10ba56e4a0..878ff5d89d8946 100644
--- a/app/javascript/mastodon/actions/notifications.js
+++ b/app/javascript/mastodon/actions/notifications.js
@@ -18,10 +18,12 @@ import {
   importFetchedStatuses,
 } from './importer';
 import { submitMarkers } from './markers';
+import { notificationsUpdate } from "./notifications_typed";
 import { register as registerPushNotifications } from './push_notifications';
 import { saveSettings } from './settings';
 
-export const NOTIFICATIONS_UPDATE      = 'NOTIFICATIONS_UPDATE';
+export * from "./notifications_typed";
+
 export const NOTIFICATIONS_UPDATE_NOOP = 'NOTIFICATIONS_UPDATE_NOOP';
 
 export const NOTIFICATIONS_EXPAND_REQUEST = 'NOTIFICATIONS_EXPAND_REQUEST';
@@ -95,12 +97,8 @@ export function updateNotifications(notification, intlMessages, intlLocale) {
         dispatch(importFetchedAccount(notification.report.target_account));
       }
 
-      dispatch({
-        type: NOTIFICATIONS_UPDATE,
-        notification,
-        usePendingItems: preferPendingItems,
-        meta: (playSound && !filtered) ? { sound: 'boop' } : undefined,
-      });
+
+      dispatch(notificationsUpdate(notification, preferPendingItems, playSound && !filtered));
 
       fetchRelatedRelationships(dispatch, [notification]);
     } else if (playSound && !filtered) {
diff --git a/app/javascript/mastodon/actions/notifications_typed.ts b/app/javascript/mastodon/actions/notifications_typed.ts
new file mode 100644
index 00000000000000..7e51fa51e7b7e8
--- /dev/null
+++ b/app/javascript/mastodon/actions/notifications_typed.ts
@@ -0,0 +1,23 @@
+import { createAction } from '@reduxjs/toolkit';
+
+import type { ApiAccountJSON } from '../api_types/accounts';
+// To be replaced once ApiNotificationJSON type exists
+interface FakeApiNotificationJSON {
+  type: string;
+  account: ApiAccountJSON;
+}
+
+export const notificationsUpdate = createAction(
+  'notifications/update',
+  ({
+    playSound,
+    ...args
+  }: {
+    notification: FakeApiNotificationJSON;
+    usePendingItems: boolean;
+    playSound: boolean;
+  }) => ({
+    payload: args,
+    meta: { playSound: playSound ? { sound: 'boop' } : undefined },
+  }),
+);
diff --git a/app/javascript/mastodon/actions/store.js b/app/javascript/mastodon/actions/store.js
index 682b0f5db7e4a0..8ab75cdc444620 100644
--- a/app/javascript/mastodon/actions/store.js
+++ b/app/javascript/mastodon/actions/store.js
@@ -11,6 +11,7 @@ const convertState = rawState =>
   fromJS(rawState, (k, v) =>
     Iterable.isIndexed(v) ? v.toList() : v.toMap());
 
+
 export function hydrateStore(rawState) {
   return dispatch => {
     const state = convertState(rawState);
diff --git a/app/javascript/mastodon/api_types/accounts.ts b/app/javascript/mastodon/api_types/accounts.ts
index 9d740c96de6977..ce55dc604ad001 100644
--- a/app/javascript/mastodon/api_types/accounts.ts
+++ b/app/javascript/mastodon/api_types/accounts.ts
@@ -31,9 +31,9 @@ export interface ApiAccountJSON {
   id: string;
   last_status_at: string;
   locked: boolean;
-  noindex: boolean;
+  noindex?: boolean;
   note: string;
-  roles: ApiAccountJSON[];
+  roles?: ApiAccountJSON[];
   statuses_count: number;
   uri: string;
   url: string;
diff --git a/app/javascript/mastodon/components/account.jsx b/app/javascript/mastodon/components/account.jsx
index e4e3c88b6f2fae..aa18ce79a5e52d 100644
--- a/app/javascript/mastodon/components/account.jsx
+++ b/app/javascript/mastodon/components/account.jsx
@@ -36,7 +36,7 @@ class Account extends ImmutablePureComponent {
 
   static propTypes = {
     size: PropTypes.number,
-    account: ImmutablePropTypes.map,
+    account: ImmutablePropTypes.record,
     onFollow: PropTypes.func.isRequired,
     onBlock: PropTypes.func.isRequired,
     onMute: PropTypes.func.isRequired,
diff --git a/app/javascript/mastodon/components/autosuggest_textarea.jsx b/app/javascript/mastodon/components/autosuggest_textarea.jsx
index 230e4f65721077..4d173af59d47c9 100644
--- a/app/javascript/mastodon/components/autosuggest_textarea.jsx
+++ b/app/javascript/mastodon/components/autosuggest_textarea.jsx
@@ -1,9 +1,9 @@
 import PropTypes from 'prop-types';
+import { useCallback, useRef, useState, useEffect, forwardRef } from 'react';
 
 import classNames from 'classnames';
 
 import ImmutablePropTypes from 'react-immutable-proptypes';
-import ImmutablePureComponent from 'react-immutable-pure-component';
 
 import Textarea from 'react-textarea-autosize';
 
@@ -37,54 +37,46 @@ const textAtCursorMatchesToken = (str, caretPosition) => {
   }
 };
 
-export default class AutosuggestTextarea extends ImmutablePureComponent {
-
-  static propTypes = {
-    value: PropTypes.string,
-    suggestions: ImmutablePropTypes.list,
-    disabled: PropTypes.bool,
-    placeholder: PropTypes.string,
-    onSuggestionSelected: PropTypes.func.isRequired,
-    onSuggestionsClearRequested: PropTypes.func.isRequired,
-    onSuggestionsFetchRequested: PropTypes.func.isRequired,
-    onChange: PropTypes.func.isRequired,
-    onKeyUp: PropTypes.func,
-    onKeyDown: PropTypes.func,
-    onPaste: PropTypes.func.isRequired,
-    autoFocus: PropTypes.bool,
-    lang: PropTypes.string,
-  };
-
-  static defaultProps = {
-    autoFocus: true,
-  };
-
-  state = {
-    suggestionsHidden: true,
-    focused: false,
-    selectedSuggestion: 0,
-    lastToken: null,
-    tokenStart: 0,
-  };
-
-  onChange = (e) => {
+const AutosuggestTextarea = forwardRef(({
+  value,
+  suggestions,
+  disabled,
+  placeholder,
+  onSuggestionSelected,
+  onSuggestionsClearRequested,
+  onSuggestionsFetchRequested,
+  onChange,
+  onKeyUp,
+  onKeyDown,
+  onPaste,
+  onFocus,
+  autoFocus = true,
+  lang,
+  children,
+}, textareaRef) => {
+
+  const [suggestionsHidden, setSuggestionsHidden] = useState(true);
+  const [selectedSuggestion, setSelectedSuggestion] = useState(0);
+  const lastTokenRef = useRef(null);
+  const tokenStartRef = useRef(0);
+
+  const handleChange = useCallback((e) => {
     const [ tokenStart, token ] = textAtCursorMatchesToken(e.target.value, e.target.selectionStart);
 
-    if (token !== null && this.state.lastToken !== token) {
-      this.setState({ lastToken: token, selectedSuggestion: 0, tokenStart });
-      this.props.onSuggestionsFetchRequested(token);
+    if (token !== null && lastTokenRef.current !== token) {
+      tokenStartRef.current = tokenStart;
+      lastTokenRef.current = token;
+      setSelectedSuggestion(0);
+      onSuggestionsFetchRequested(token);
     } else if (token === null) {
-      this.setState({ lastToken: null });
-      this.props.onSuggestionsClearRequested();
+      lastTokenRef.current = null;
+      onSuggestionsClearRequested();
     }
 
-    this.props.onChange(e);
-  };
-
-  onKeyDown = (e) => {
-    const { suggestions, disabled } = this.props;
-    const { selectedSuggestion, suggestionsHidden } = this.state;
+    onChange(e);
+  }, [onSuggestionsFetchRequested, onSuggestionsClearRequested, onChange, setSelectedSuggestion]);
 
+  const handleKeyDown = useCallback((e) => {
     if (disabled) {
       e.preventDefault();
       return;
@@ -102,80 +94,75 @@ export default class AutosuggestTextarea extends ImmutablePureComponent {
         document.querySelector('.ui').parentElement.focus();
       } else {
         e.preventDefault();
-        this.setState({ suggestionsHidden: true });
+        setSuggestionsHidden(true);
       }
 
       break;
     case 'ArrowDown':
       if (suggestions.size > 0 && !suggestionsHidden) {
         e.preventDefault();
-        this.setState({ selectedSuggestion: Math.min(selectedSuggestion + 1, suggestions.size - 1) });
+        setSelectedSuggestion(Math.min(selectedSuggestion + 1, suggestions.size - 1));
       }
 
       break;
     case 'ArrowUp':
       if (suggestions.size > 0 && !suggestionsHidden) {
         e.preventDefault();
-        this.setState({ selectedSuggestion: Math.max(selectedSuggestion - 1, 0) });
+        setSelectedSuggestion(Math.max(selectedSuggestion - 1, 0));
       }
 
       break;
     case 'Enter':
     case 'Tab':
       // Select suggestion
-      if (this.state.lastToken !== null && suggestions.size > 0 && !suggestionsHidden) {
+      if (lastTokenRef.current !== null && suggestions.size > 0 && !suggestionsHidden) {
         e.preventDefault();
         e.stopPropagation();
-        this.props.onSuggestionSelected(this.state.tokenStart, this.state.lastToken, suggestions.get(selectedSuggestion));
+        onSuggestionSelected(tokenStartRef.current, lastTokenRef.current, suggestions.get(selectedSuggestion));
       }
 
       break;
     }
 
-    if (e.defaultPrevented || !this.props.onKeyDown) {
+    if (e.defaultPrevented || !onKeyDown) {
       return;
     }
 
-    this.props.onKeyDown(e);
-  };
+    onKeyDown(e);
+  }, [disabled, suggestions, suggestionsHidden, selectedSuggestion, setSelectedSuggestion, setSuggestionsHidden, onSuggestionSelected, onKeyDown]);
 
-  onBlur = () => {
-    this.setState({ suggestionsHidden: true, focused: false });
-  };
+  const handleBlur = useCallback(() => {
+    setSuggestionsHidden(true);
+  }, [setSuggestionsHidden]);
 
-  onFocus = (e) => {
-    this.setState({ focused: true });
-    if (this.props.onFocus) {
-      this.props.onFocus(e);
+  const handleFocus = useCallback((e) => {
+    if (onFocus) {
+      onFocus(e);
     }
-  };
+  }, [onFocus]);
 
-  onSuggestionClick = (e) => {
-    const suggestion = this.props.suggestions.get(e.currentTarget.getAttribute('data-index'));
+  const handleSuggestionClick = useCallback((e) => {
+    const suggestion = suggestions.get(e.currentTarget.getAttribute('data-index'));
     e.preventDefault();
-    this.props.onSuggestionSelected(this.state.tokenStart, this.state.lastToken, suggestion);
-    this.textarea.focus();
-  };
+    onSuggestionSelected(tokenStartRef.current, lastTokenRef.current, suggestion);
+    textareaRef.current?.focus();
+  }, [suggestions, onSuggestionSelected, textareaRef]);
 
-  UNSAFE_componentWillReceiveProps (nextProps) {
-    if (nextProps.suggestions !== this.props.suggestions && nextProps.suggestions.size > 0 && this.state.suggestionsHidden && this.state.focused) {
-      this.setState({ suggestionsHidden: false });
-    }
-  }
-
-  setTextarea = (c) => {
-    this.textarea = c;
-  };
-
-  onPaste = (e) => {
+  const handlePaste = useCallback((e) => {
     if (e.clipboardData && e.clipboardData.files.length === 1) {
-      this.props.onPaste(e.clipboardData.files);
+      onPaste(e.clipboardData.files);
       e.preventDefault();
     }
-  };
+  }, [onPaste]);
+
+  // Show the suggestions again whenever they change and the textarea is focused
+  useEffect(() => {
+    if (suggestions.size > 0 && textareaRef.current === document.activeElement) {
+      setSuggestionsHidden(false);
+    }
+  }, [suggestions, textareaRef, setSuggestionsHidden]);
 
-  renderSuggestion = (suggestion, i) => {
-    const { selectedSuggestion } = this.state;
+  const renderSuggestion = (suggestion, i) => {
     let inner, key;
 
     if (suggestion.type === 'emoji') {
@@ -190,50 +177,64 @@ export default class AutosuggestTextarea extends ImmutablePureComponent {
     }
 
     return (
-      <div role='button' tabIndex={0} key={key} data-index={i} className={classNames('autosuggest-textarea__suggestions__item', { selected: i === selectedSuggestion })} onMouseDown={this.onSuggestionClick}>
+      <div role='button' tabIndex={0} key={key} data-index={i} className={classNames('autosuggest-textarea__suggestions__item', { selected: i === selectedSuggestion })} onMouseDown={handleSuggestionClick}>
         {inner}
       </div>
     );
   };
 
-  render () {
-    const { value, suggestions, disabled, placeholder, onKeyUp, autoFocus, lang, children } = this.props;
-    const { suggestionsHidden } = this.state;
-
-    return [
-      <div className='compose-form__autosuggest-wrapper' key='autosuggest-wrapper'>
-        <div className='autosuggest-textarea'>
-          <label>
-            <span style={{ display: 'none' }}>{placeholder}</span>
-
-            <Textarea
-              ref={this.setTextarea}
-              className='autosuggest-textarea__textarea'
-              disabled={disabled}
-              placeholder={placeholder}
-              autoFocus={autoFocus}
-              value={value}
-              onChange={this.onChange}
-              onKeyDown={this.onKeyDown}
-              onKeyUp={onKeyUp}
-              onFocus={this.onFocus}
-              onBlur={this.onBlur}
-              onPaste={this.onPaste}
-              dir='auto'
-              aria-autocomplete='list'
-              lang={lang}
-            />
-          </label>
-        </div>
-        {children}
-      </div>,
-
-      <div className='autosuggest-textarea__suggestions-wrapper' key='suggestions-wrapper'>
-        <div className={`autosuggest-textarea__suggestions ${suggestionsHidden || suggestions.isEmpty() ? '' : 'autosuggest-textarea__suggestions--visible'}`}>
-          {suggestions.map(this.renderSuggestion)}
-        </div>
-      </div>,
-    ];
-  }
+  return [
+    <div className='compose-form__autosuggest-wrapper' key='autosuggest-wrapper'>
+      <div className='autosuggest-textarea'>
+        <label>
+          <span style={{ display: 'none' }}>{placeholder}</span>
+
+          <Textarea
+            ref={textareaRef}
+            className='autosuggest-textarea__textarea'
+            disabled={disabled}
+            placeholder={placeholder}
+            autoFocus={autoFocus}
+            value={value}
+            onChange={handleChange}
+            onKeyDown={handleKeyDown}
+            onKeyUp={onKeyUp}
+            onFocus={handleFocus}
+            onBlur={handleBlur}
+            onPaste={handlePaste}
+            dir='auto'
+            aria-autocomplete='list'
+            lang={lang}
+          />
+        </label>
+      </div>
+      {children}
+    </div>,
+
+    <div className='autosuggest-textarea__suggestions-wrapper' key='suggestions-wrapper'>
+      <div className={`autosuggest-textarea__suggestions ${suggestionsHidden || suggestions.isEmpty() ? '' : 'autosuggest-textarea__suggestions--visible'}`}>
+        {suggestions.map(renderSuggestion)}
+      </div>
+    </div>,
+  ];
+});
+
+AutosuggestTextarea.propTypes = {
+  value: PropTypes.string,
+  suggestions: ImmutablePropTypes.list,
+  disabled: PropTypes.bool,
+  placeholder: PropTypes.string,
+  onSuggestionSelected: PropTypes.func.isRequired,
+  onSuggestionsClearRequested: PropTypes.func.isRequired,
+  onSuggestionsFetchRequested: PropTypes.func.isRequired,
+  onChange: PropTypes.func.isRequired,
+  onKeyUp: PropTypes.func,
+  onKeyDown: PropTypes.func,
+  onPaste: PropTypes.func.isRequired,
+  onFocus:PropTypes.func,
+  children: PropTypes.node,
+  autoFocus: PropTypes.bool,
+  lang: PropTypes.string,
+};
 
-}
+export default AutosuggestTextarea;
diff --git a/app/javascript/mastodon/components/avatar.tsx b/app/javascript/mastodon/components/avatar.tsx
index 5f9bb390e82ea5..77bd4234094766 100644
--- a/app/javascript/mastodon/components/avatar.tsx
+++ b/app/javascript/mastodon/components/avatar.tsx
@@ -1,7 +1,8 @@
 import classNames from 'classnames';
 
+import type { Account } from 'mastodon/models/account';
+
 import { useHovering } from '../../hooks/useHovering';
-import type { Account } from '../../types/resources';
 import { autoPlayGif } from '../initial_state';
 
 interface Props {
diff --git a/app/javascript/mastodon/components/avatar_overlay.tsx b/app/javascript/mastodon/components/avatar_overlay.tsx
index 61de9d0beba488..f98cfcc38b4eeb 100644
--- a/app/javascript/mastodon/components/avatar_overlay.tsx
+++ b/app/javascript/mastodon/components/avatar_overlay.tsx
@@ -1,5 +1,6 @@
+import type { Account } from 'mastodon/models/account';
+
 import { useHovering } from '../../hooks/useHovering';
-import type { Account } from '../../types/resources';
 import { autoPlayGif } from '../initial_state';
 
 interface Props {
diff --git a/app/javascript/mastodon/components/display_name.tsx b/app/javascript/mastodon/components/display_name.tsx
index 82a42bb022636c..8409244827ebb4 100644
--- a/app/javascript/mastodon/components/display_name.tsx
+++ b/app/javascript/mastodon/components/display_name.tsx
@@ -2,7 +2,8 @@ import React from 'react';
 
 import type { List } from 'immutable';
 
-import type { Account } from '../../types/resources';
+import type { Account } from 'mastodon/models/account';
+
 import { autoPlayGif } from '../initial_state';
 
 import { Skeleton } from './skeleton';
diff --git a/app/javascript/mastodon/components/icon.tsx b/app/javascript/mastodon/components/icon.tsx
index dbf5839606597b..f0af11f7f69f5f 100644
--- a/app/javascript/mastodon/components/icon.tsx
+++ b/app/javascript/mastodon/components/icon.tsx
@@ -2,6 +2,8 @@ import classNames from 'classnames';
 
 import { ReactComponent as CheckBoxOutlineBlankIcon } from '@material-symbols/svg-600/outlined/check_box_outline_blank.svg';
 
+import { isProduction } from 'mastodon/utils/environment';
+
 interface SVGPropsWithTitle extends React.SVGProps<SVGSVGElement> {
   title?: string;
 }
@@ -24,7 +26,7 @@ export const Icon: React.FC<Props> = ({
 }) => {
   // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
   if (!IconComponent) {
-    if (process.env.NODE_ENV !== 'production') {
+    if (!isProduction()) {
       throw new Error(
         `<Icon id="${id}" className="${className}"> is missing an "icon" prop.`,
       );
diff --git a/app/javascript/mastodon/components/inline_account.jsx b/app/javascript/mastodon/components/inline_account.jsx
index f9767c29d42539..792c412287759e 100644
--- a/app/javascript/mastodon/components/inline_account.jsx
+++ b/app/javascript/mastodon/components/inline_account.jsx
@@ -19,7 +19,7 @@ const makeMapStateToProps = () => {
 class InlineAccount extends PureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
   };
 
   render () {
diff --git a/app/javascript/mastodon/components/router.tsx b/app/javascript/mastodon/components/router.tsx
index fe50fc2ba9014e..42b926659cb713 100644
--- a/app/javascript/mastodon/components/router.tsx
+++ b/app/javascript/mastodon/components/router.tsx
@@ -11,6 +11,7 @@ import type {
 import { createBrowserHistory } from 'history';
 
 import { layoutFromWindow } from 'mastodon/is_mobile';
+import { isDevelopment } from 'mastodon/utils/environment';
 
 interface MastodonLocationState {
   fromMastodon?: boolean;
@@ -40,7 +41,7 @@ function normalizePath(
   } else if (
     location.state !== undefined &&
     state !== undefined &&
-    process.env.NODE_ENV === 'development'
+    isDevelopment()
   ) {
     // eslint-disable-next-line no-console
     console.log(
diff --git a/app/javascript/mastodon/components/status.jsx b/app/javascript/mastodon/components/status.jsx
index e065b4816ac480..c141ee2da3ef19 100644
--- a/app/javascript/mastodon/components/status.jsx
+++ b/app/javascript/mastodon/components/status.jsx
@@ -80,7 +80,7 @@ class Status extends ImmutablePureComponent {
 
   static propTypes = {
     status: ImmutablePropTypes.map,
-    account: ImmutablePropTypes.map,
+    account: ImmutablePropTypes.record,
     previousId: PropTypes.string,
     nextInReplyToId: PropTypes.string,
     rootId: PropTypes.string,
diff --git a/app/javascript/mastodon/containers/mastodon.jsx b/app/javascript/mastodon/containers/mastodon.jsx
index 59efc80570dc6c..87708da191bb56 100644
--- a/app/javascript/mastodon/containers/mastodon.jsx
+++ b/app/javascript/mastodon/containers/mastodon.jsx
@@ -17,8 +17,9 @@ import UI from 'mastodon/features/ui';
 import initialState, { title as siteTitle } from 'mastodon/initial_state';
 import { IntlProvider } from 'mastodon/locales';
 import { store } from 'mastodon/store';
+import { isProduction } from 'mastodon/utils/environment';
 
-const title = process.env.NODE_ENV === 'production' ? siteTitle : `${siteTitle} (Dev)`;
+const title = isProduction() ? siteTitle : `${siteTitle} (Dev)`;
 
 const hydrateAction = hydrateStore(initialState);
 
diff --git a/app/javascript/mastodon/features/account/components/account_note.jsx b/app/javascript/mastodon/features/account/components/account_note.jsx
index bab523acf63bfe..272a4ee312c08d 100644
--- a/app/javascript/mastodon/features/account/components/account_note.jsx
+++ b/app/javascript/mastodon/features/account/components/account_note.jsx
@@ -49,7 +49,7 @@ class InlineAlert extends PureComponent {
 class AccountNote extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     value: PropTypes.string,
     onSave: PropTypes.func.isRequired,
     intl: PropTypes.object.isRequired,
diff --git a/app/javascript/mastodon/features/account/components/featured_tags.jsx b/app/javascript/mastodon/features/account/components/featured_tags.jsx
index bbbec1b86470c2..4d7dd86560a34d 100644
--- a/app/javascript/mastodon/features/account/components/featured_tags.jsx
+++ b/app/javascript/mastodon/features/account/components/featured_tags.jsx
@@ -15,7 +15,7 @@ const messages = defineMessages({
 class FeaturedTags extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map,
+    account: ImmutablePropTypes.record,
     featuredTags: ImmutablePropTypes.list,
     tagged: PropTypes.string,
     intl: PropTypes.object.isRequired,
diff --git a/app/javascript/mastodon/features/account/components/follow_request_note.jsx b/app/javascript/mastodon/features/account/components/follow_request_note.jsx
index 0e597a70505771..685c282df27761 100644
--- a/app/javascript/mastodon/features/account/components/follow_request_note.jsx
+++ b/app/javascript/mastodon/features/account/components/follow_request_note.jsx
@@ -11,7 +11,7 @@ import { Icon }  from 'mastodon/components/icon';
 export default class FollowRequestNote extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
   };
 
   render () {
diff --git a/app/javascript/mastodon/features/account/components/header.jsx b/app/javascript/mastodon/features/account/components/header.jsx
index 76074225adf5c2..e546c756934656 100644
--- a/app/javascript/mastodon/features/account/components/header.jsx
+++ b/app/javascript/mastodon/features/account/components/header.jsx
@@ -91,7 +91,7 @@ const dateFormatOptions = {
 class Header extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map,
+    account: ImmutablePropTypes.record,
     identity_props: ImmutablePropTypes.list,
     onFollow: PropTypes.func.isRequired,
     onBlock: PropTypes.func.isRequired,
diff --git a/app/javascript/mastodon/features/account_timeline/components/header.jsx b/app/javascript/mastodon/features/account_timeline/components/header.jsx
index aede7e495744d0..7de8d3771b4683 100644
--- a/app/javascript/mastodon/features/account_timeline/components/header.jsx
+++ b/app/javascript/mastodon/features/account_timeline/components/header.jsx
@@ -17,7 +17,7 @@ import MovedNote from './moved_note';
 class Header extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map,
+    account: ImmutablePropTypes.record,
     onFollow: PropTypes.func.isRequired,
     onBlock: PropTypes.func.isRequired,
     onMention: PropTypes.func.isRequired,
diff --git a/app/javascript/mastodon/features/account_timeline/components/limited_account_hint.jsx b/app/javascript/mastodon/features/account_timeline/components/limited_account_hint.jsx
deleted file mode 100644
index 59b7358233e8bd..00000000000000
--- a/app/javascript/mastodon/features/account_timeline/components/limited_account_hint.jsx
+++ /dev/null
@@ -1,40 +0,0 @@
-import PropTypes from 'prop-types';
-import { PureComponent } from 'react';
-
-import { FormattedMessage } from 'react-intl';
-
-import { connect } from 'react-redux';
-
-import { revealAccount } from 'mastodon/actions/accounts';
-import { Button } from 'mastodon/components/button';
-import { domain } from 'mastodon/initial_state';
-
-const mapDispatchToProps = (dispatch, { accountId }) => ({
-
-  reveal () {
-    dispatch(revealAccount(accountId));
-  },
-
-});
-
-class LimitedAccountHint extends PureComponent {
-
-  static propTypes = {
-    accountId: PropTypes.string.isRequired,
-    reveal: PropTypes.func,
-  };
-
-  render () {
-    const { reveal } = this.props;
-
-    return (
-      <div className='limited-account-hint'>
-        <p><FormattedMessage id='limited_account_hint.title' defaultMessage='This profile has been hidden by the moderators of {domain}.' values={{ domain }} /></p>
-        <Button onClick={reveal}><FormattedMessage id='limited_account_hint.action' defaultMessage='Show profile anyway' /></Button>
-      </div>
-    );
-  }
-
-}
-
-export default connect(() => {}, mapDispatchToProps)(LimitedAccountHint);
diff --git a/app/javascript/mastodon/features/account_timeline/components/limited_account_hint.tsx b/app/javascript/mastodon/features/account_timeline/components/limited_account_hint.tsx
new file mode 100644
index 00000000000000..f06bf574a77810
--- /dev/null
+++ b/app/javascript/mastodon/features/account_timeline/components/limited_account_hint.tsx
@@ -0,0 +1,35 @@
+import { useCallback } from 'react';
+
+import { FormattedMessage } from 'react-intl';
+
+import { revealAccount } from 'mastodon/actions/accounts_typed';
+import { Button } from 'mastodon/components/button';
+import { domain } from 'mastodon/initial_state';
+import { useAppDispatch } from 'mastodon/store';
+
+export const LimitedAccountHint: React.FC<{ accountId: string }> = ({
+  accountId,
+}) => {
+  const dispatch = useAppDispatch();
+  const reveal = useCallback(() => {
+    dispatch(revealAccount({ id: accountId }));
+  }, [dispatch, accountId]);
+
+  return (
+    <div className='limited-account-hint'>
+      <p>
+        <FormattedMessage
+          id='limited_account_hint.title'
+          defaultMessage='This profile has been hidden by the moderators of {domain}.'
+          values={{ domain }}
+        />
+      </p>
+      <Button onClick={reveal}>
+        <FormattedMessage
+          id='limited_account_hint.action'
+          defaultMessage='Show profile anyway'
+        />
+      </Button>
+    </div>
+  );
+};
diff --git a/app/javascript/mastodon/features/account_timeline/index.jsx b/app/javascript/mastodon/features/account_timeline/index.jsx
index 5dae66b46365b0..5ec029593d5344 100644
--- a/app/javascript/mastodon/features/account_timeline/index.jsx
+++ b/app/javascript/mastodon/features/account_timeline/index.jsx
@@ -21,7 +21,7 @@ import { LoadingIndicator } from '../../components/loading_indicator';
 import StatusList from '../../components/status_list';
 import Column from '../ui/components/column';
 
-import LimitedAccountHint from './components/limited_account_hint';
+import { LimitedAccountHint } from './components/limited_account_hint';
 import HeaderContainer from './containers/header_container';
 
 const emptyList = ImmutableList();
diff --git a/app/javascript/mastodon/features/compose/components/action_bar.jsx b/app/javascript/mastodon/features/compose/components/action_bar.jsx
index f7488cf5541857..3e2109092576f7 100644
--- a/app/javascript/mastodon/features/compose/components/action_bar.jsx
+++ b/app/javascript/mastodon/features/compose/components/action_bar.jsx
@@ -28,7 +28,7 @@ const messages = defineMessages({
 class ActionBar extends PureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     onLogout: PropTypes.func.isRequired,
     intl: PropTypes.object.isRequired,
   };
diff --git a/app/javascript/mastodon/features/compose/components/autosuggest_account.jsx b/app/javascript/mastodon/features/compose/components/autosuggest_account.jsx
index ebda0590e3eb20..0a73bc1020f4f6 100644
--- a/app/javascript/mastodon/features/compose/components/autosuggest_account.jsx
+++ b/app/javascript/mastodon/features/compose/components/autosuggest_account.jsx
@@ -7,7 +7,7 @@ import { DisplayName } from '../../../components/display_name';
 export default class AutosuggestAccount extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
   };
 
   render () {
diff --git a/app/javascript/mastodon/features/compose/components/compose_form.jsx b/app/javascript/mastodon/features/compose/components/compose_form.jsx
index 5bd990a302c18d..3b752f252d0099 100644
--- a/app/javascript/mastodon/features/compose/components/compose_form.jsx
+++ b/app/javascript/mastodon/features/compose/components/compose_form.jsx
@@ -1,4 +1,5 @@
 import PropTypes from 'prop-types';
+import { createRef } from 'react';
 
 import { defineMessages, injectIntl } from 'react-intl';
 
@@ -80,6 +81,11 @@ class ComposeForm extends ImmutablePureComponent {
     highlighted: false,
   };
 
+  constructor(props) {
+    super(props);
+    this.textareaRef = createRef(null);
+  }
+
   handleChange = (e) => {
     this.props.onChange(e.target.value);
   };
@@ -103,10 +109,10 @@ class ComposeForm extends ImmutablePureComponent {
   };
 
   handleSubmit = (e) => {
-    if (this.props.text !== this.autosuggestTextarea.textarea.value) {
+    if (this.props.text !== this.textareaRef.current.value) {
       // Something changed the text inside the textarea (e.g. browser extensions like Grammarly)
       // Update the state to match the current text
-      this.props.onChange(this.autosuggestTextarea.textarea.value);
+      this.props.onChange(this.textareaRef.current.value);
     }
 
     if (!this.canSubmit()) {
@@ -185,26 +191,22 @@ class ComposeForm extends ImmutablePureComponent {
       // immediately selectable, we have to wait for observers to run, as
       // described in https://github.com/WICG/inert#performance-and-gotchas
       Promise.resolve().then(() => {
-        this.autosuggestTextarea.textarea.setSelectionRange(selectionStart, selectionEnd);
-        this.autosuggestTextarea.textarea.focus();
+        this.textareaRef.current.setSelectionRange(selectionStart, selectionEnd);
+        this.textareaRef.current.focus();
         this.setState({ highlighted: true });
         this.timeout = setTimeout(() => this.setState({ highlighted: false }), 700);
       }).catch(console.error);
     } else if(prevProps.isSubmitting && !this.props.isSubmitting) {
-      this.autosuggestTextarea.textarea.focus();
+      this.textareaRef.current.focus();
     } else if (this.props.spoiler !== prevProps.spoiler) {
       if (this.props.spoiler) {
         this.spoilerText.input.focus();
       } else if (prevProps.spoiler) {
-        this.autosuggestTextarea.textarea.focus();
+        this.textareaRef.current.focus();
       }
     }
   };
 
-  setAutosuggestTextarea = (c) => {
-    this.autosuggestTextarea = c;
-  };
-
   setSpoilerText = (c) => {
     this.spoilerText = c;
   };
@@ -215,7 +217,7 @@ class ComposeForm extends ImmutablePureComponent {
 
   handleEmojiPick = (data) => {
     const { text }     = this.props;
-    const position     = this.autosuggestTextarea.textarea.selectionStart;
+    const position     = this.textareaRef.current.selectionStart;
     const needsSpace   = data.custom && position > 0 && !allowedAroundShortCode.includes(text[position - 1]);
 
     this.props.onPickEmoji(position, data, needsSpace);
@@ -264,7 +266,7 @@ class ComposeForm extends ImmutablePureComponent {
 
         <div className={classNames('compose-form__highlightable', { active: highlighted })}>
           <AutosuggestTextarea
-            ref={this.setAutosuggestTextarea}
+            ref={this.textareaRef}
             placeholder={intl.formatMessage(messages.placeholder)}
             disabled={disabled}
             value={this.props.text}
diff --git a/app/javascript/mastodon/features/compose/components/navigation_bar.jsx b/app/javascript/mastodon/features/compose/components/navigation_bar.jsx
index e842ab1f8d5037..2f0bb79f891827 100644
--- a/app/javascript/mastodon/features/compose/components/navigation_bar.jsx
+++ b/app/javascript/mastodon/features/compose/components/navigation_bar.jsx
@@ -14,7 +14,7 @@ import ActionBar from './action_bar';
 export default class NavigationBar extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     onLogout: PropTypes.func.isRequired,
     onClose: PropTypes.func,
   };
diff --git a/app/javascript/mastodon/features/directory/components/account_card.jsx b/app/javascript/mastodon/features/directory/components/account_card.jsx
index a5e5717b329df0..ff1f8a653b5561 100644
--- a/app/javascript/mastodon/features/directory/components/account_card.jsx
+++ b/app/javascript/mastodon/features/directory/components/account_card.jsx
@@ -102,7 +102,7 @@ const mapDispatchToProps = (dispatch, { intl }) => ({
 class AccountCard extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     intl: PropTypes.object.isRequired,
     onFollow: PropTypes.func.isRequired,
     onBlock: PropTypes.func.isRequired,
diff --git a/app/javascript/mastodon/features/follow_requests/components/account_authorize.jsx b/app/javascript/mastodon/features/follow_requests/components/account_authorize.jsx
index b5dfe510e90946..ca2b454143a468 100644
--- a/app/javascript/mastodon/features/follow_requests/components/account_authorize.jsx
+++ b/app/javascript/mastodon/features/follow_requests/components/account_authorize.jsx
@@ -22,7 +22,7 @@ const messages = defineMessages({
 class AccountAuthorize extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     onAuthorize: PropTypes.func.isRequired,
     onReject: PropTypes.func.isRequired,
     intl: PropTypes.object.isRequired,
diff --git a/app/javascript/mastodon/features/followers/index.jsx b/app/javascript/mastodon/features/followers/index.jsx
index fc0ce8ab30119b..e50b2171a0a256 100644
--- a/app/javascript/mastodon/features/followers/index.jsx
+++ b/app/javascript/mastodon/features/followers/index.jsx
@@ -23,7 +23,7 @@ import { ColumnBackButton } from '../../components/column_back_button';
 import { LoadingIndicator } from '../../components/loading_indicator';
 import ScrollableList from '../../components/scrollable_list';
 import AccountContainer from '../../containers/account_container';
-import LimitedAccountHint from '../account_timeline/components/limited_account_hint';
+import { LimitedAccountHint } from '../account_timeline/components/limited_account_hint';
 import HeaderContainer from '../account_timeline/containers/header_container';
 import Column from '../ui/components/column';
 
diff --git a/app/javascript/mastodon/features/following/index.jsx b/app/javascript/mastodon/features/following/index.jsx
index fb02d179505d94..73e77aadd78237 100644
--- a/app/javascript/mastodon/features/following/index.jsx
+++ b/app/javascript/mastodon/features/following/index.jsx
@@ -23,7 +23,7 @@ import { ColumnBackButton } from '../../components/column_back_button';
 import { LoadingIndicator } from '../../components/loading_indicator';
 import ScrollableList from '../../components/scrollable_list';
 import AccountContainer from '../../containers/account_container';
-import LimitedAccountHint from '../account_timeline/components/limited_account_hint';
+import { LimitedAccountHint } from '../account_timeline/components/limited_account_hint';
 import HeaderContainer from '../account_timeline/containers/header_container';
 import Column from '../ui/components/column';
 
diff --git a/app/javascript/mastodon/features/list_adder/components/account.jsx b/app/javascript/mastodon/features/list_adder/components/account.jsx
index 31a2e963795e12..94a90726e33342 100644
--- a/app/javascript/mastodon/features/list_adder/components/account.jsx
+++ b/app/javascript/mastodon/features/list_adder/components/account.jsx
@@ -21,7 +21,7 @@ const makeMapStateToProps = () => {
 class Account extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
   };
 
   render () {
diff --git a/app/javascript/mastodon/features/list_editor/components/account.jsx b/app/javascript/mastodon/features/list_editor/components/account.jsx
index f38c7d93a7c8f6..18d5e905cbc0b7 100644
--- a/app/javascript/mastodon/features/list_editor/components/account.jsx
+++ b/app/javascript/mastodon/features/list_editor/components/account.jsx
@@ -39,7 +39,7 @@ const mapDispatchToProps = (dispatch, { accountId }) => ({
 class Account extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     intl: PropTypes.object.isRequired,
     onRemove: PropTypes.func.isRequired,
     onAdd: PropTypes.func.isRequired,
diff --git a/app/javascript/mastodon/features/notifications/components/follow_request.jsx b/app/javascript/mastodon/features/notifications/components/follow_request.jsx
index c10633beebcc76..03420b6c01e6e8 100644
--- a/app/javascript/mastodon/features/notifications/components/follow_request.jsx
+++ b/app/javascript/mastodon/features/notifications/components/follow_request.jsx
@@ -22,7 +22,7 @@ const messages = defineMessages({
 class FollowRequest extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     onAuthorize: PropTypes.func.isRequired,
     onReject: PropTypes.func.isRequired,
     intl: PropTypes.object.isRequired,
diff --git a/app/javascript/mastodon/features/notifications/components/report.jsx b/app/javascript/mastodon/features/notifications/components/report.jsx
index cb50b62cdc2ad1..52d6bfee9dbd84 100644
--- a/app/javascript/mastodon/features/notifications/components/report.jsx
+++ b/app/javascript/mastodon/features/notifications/components/report.jsx
@@ -20,7 +20,7 @@ const messages = defineMessages({
 class Report extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     report: ImmutablePropTypes.map.isRequired,
     hidden: PropTypes.bool,
     intl: PropTypes.object.isRequired,
diff --git a/app/javascript/mastodon/features/onboarding/index.jsx b/app/javascript/mastodon/features/onboarding/index.jsx
index 7b8a41faa59f13..51d4b71f246404 100644
--- a/app/javascript/mastodon/features/onboarding/index.jsx
+++ b/app/javascript/mastodon/features/onboarding/index.jsx
@@ -46,7 +46,7 @@ const mapStateToProps = () => {
 class Onboarding extends ImmutablePureComponent {
   static propTypes = {
     dispatch: PropTypes.func.isRequired,
-    account: ImmutablePropTypes.map,
+    account: ImmutablePropTypes.record,
     ...WithRouterPropTypes,
   };
 
diff --git a/app/javascript/mastodon/features/onboarding/share.jsx b/app/javascript/mastodon/features/onboarding/share.jsx
index 8e01701eb3f394..33492442238188 100644
--- a/app/javascript/mastodon/features/onboarding/share.jsx
+++ b/app/javascript/mastodon/features/onboarding/share.jsx
@@ -145,7 +145,7 @@ class Share extends PureComponent {
 
   static propTypes = {
     onBack: PropTypes.func,
-    account: ImmutablePropTypes.map,
+    account: ImmutablePropTypes.record,
     intl: PropTypes.object,
   };
 
diff --git a/app/javascript/mastodon/features/picture_in_picture/components/header.jsx b/app/javascript/mastodon/features/picture_in_picture/components/header.jsx
index b7fd9d1276f24e..80a13bd2e35b81 100644
--- a/app/javascript/mastodon/features/picture_in_picture/components/header.jsx
+++ b/app/javascript/mastodon/features/picture_in_picture/components/header.jsx
@@ -27,7 +27,7 @@ class Header extends ImmutablePureComponent {
   static propTypes = {
     accountId: PropTypes.string.isRequired,
     statusId: PropTypes.string.isRequired,
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     onClose: PropTypes.func.isRequired,
     intl: PropTypes.object.isRequired,
   };
diff --git a/app/javascript/mastodon/features/report/thanks.jsx b/app/javascript/mastodon/features/report/thanks.jsx
index 146d4b3897673e..904c4477013154 100644
--- a/app/javascript/mastodon/features/report/thanks.jsx
+++ b/app/javascript/mastodon/features/report/thanks.jsx
@@ -20,7 +20,7 @@ class Thanks extends PureComponent {
   static propTypes = {
     submitted: PropTypes.bool,
     onClose: PropTypes.func.isRequired,
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     dispatch: PropTypes.func.isRequired,
   };
 
diff --git a/app/javascript/mastodon/features/ui/components/focal_point_modal.jsx b/app/javascript/mastodon/features/ui/components/focal_point_modal.jsx
index 40481e2c8767dd..5353ebdb8aa404 100644
--- a/app/javascript/mastodon/features/ui/components/focal_point_modal.jsx
+++ b/app/javascript/mastodon/features/ui/components/focal_point_modal.jsx
@@ -110,7 +110,7 @@ class FocalPointModal extends ImmutablePureComponent {
 
   static propTypes = {
     media: ImmutablePropTypes.map.isRequired,
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     isUploadingThumbnail: PropTypes.bool,
     onSave: PropTypes.func.isRequired,
     onChangeDescription: PropTypes.func.isRequired,
diff --git a/app/javascript/mastodon/features/ui/components/report_modal.jsx b/app/javascript/mastodon/features/ui/components/report_modal.jsx
index 2b6f04207ebdd1..3fd8ff127d8789 100644
--- a/app/javascript/mastodon/features/ui/components/report_modal.jsx
+++ b/app/javascript/mastodon/features/ui/components/report_modal.jsx
@@ -41,7 +41,7 @@ class ReportModal extends ImmutablePureComponent {
     statusId: PropTypes.string,
     dispatch: PropTypes.func.isRequired,
     intl: PropTypes.object.isRequired,
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
   };
 
   state = {
diff --git a/app/javascript/mastodon/initial_state.js b/app/javascript/mastodon/initial_state.js
index 598e7337480d65..b02469f993348b 100644
--- a/app/javascript/mastodon/initial_state.js
+++ b/app/javascript/mastodon/initial_state.js
@@ -1,43 +1,5 @@
 // @ts-check
 
-/**
- * @typedef Emoji
- * @property {string} shortcode
- * @property {string} static_url
- * @property {string} url
- */
-
-/**
- * @typedef AccountField
- * @property {string} name
- * @property {string} value
- * @property {string} verified_at
- */
-
-/**
- * @typedef Account
- * @property {string} acct
- * @property {string} avatar
- * @property {string} avatar_static
- * @property {boolean} bot
- * @property {string} created_at
- * @property {boolean=} discoverable
- * @property {string} display_name
- * @property {Emoji[]} emojis
- * @property {AccountField[]} fields
- * @property {number} followers_count
- * @property {number} following_count
- * @property {boolean} group
- * @property {string} header
- * @property {string} header_static
- * @property {string} id
- * @property {string=} last_status_at
- * @property {boolean} locked
- * @property {string} note
- * @property {number} statuses_count
- * @property {string} url
- * @property {string} username
- */
 
 /**
  * @typedef {[code: string, name: string, localName: string]} InitialStateLanguage
@@ -85,7 +47,7 @@
 
 /**
  * @typedef InitialState
- * @property {Record<string, Account>} accounts
+ * @property {Record<string, import("./api_types/accounts").ApiAccountJSON>} accounts
  * @property {InitialStateLanguage[]} languages
  * @property {boolean=} critical_updates_pending
  * @property {InitialStateMeta} meta
diff --git a/app/javascript/mastodon/locales/de.json b/app/javascript/mastodon/locales/de.json
index 76b37ef44b06df..3fcab71d708115 100644
--- a/app/javascript/mastodon/locales/de.json
+++ b/app/javascript/mastodon/locales/de.json
@@ -425,7 +425,7 @@
   "notification.admin.report": "{name} meldete {target}",
   "notification.admin.sign_up": "{name} registrierte sich",
   "notification.favourite": "{name} favorisierte deinen Beitrag",
-  "notification.follow": "{name} folgt dir jetzt",
+  "notification.follow": "{name} folgt dir",
   "notification.follow_request": "{name} möchte dir folgen",
   "notification.mention": "{name} erwähnte dich",
   "notification.own_poll": "Deine Umfrage ist beendet",
diff --git a/app/javascript/mastodon/locales/global_locale.ts b/app/javascript/mastodon/locales/global_locale.ts
index 2d4329c7645023..8d142b8b049224 100644
--- a/app/javascript/mastodon/locales/global_locale.ts
+++ b/app/javascript/mastodon/locales/global_locale.ts
@@ -1,3 +1,5 @@
+import { isDevelopment } from 'mastodon/utils/environment';
+
 export interface LocaleData {
   locale: string;
   messages: Record<string, string>;
@@ -11,7 +13,7 @@ export function setLocale(locale: LocaleData) {
 
 export function getLocale(): LocaleData {
   if (!loadedLocale) {
-    if (process.env.NODE_ENV === 'development') {
+    if (isDevelopment()) {
       throw new Error('getLocale() called before any locale has been set');
     } else {
       return { locale: 'unknown', messages: {} };
diff --git a/app/javascript/mastodon/locales/he.json b/app/javascript/mastodon/locales/he.json
index 01618118a316c5..a8cb2ec27663b3 100644
--- a/app/javascript/mastodon/locales/he.json
+++ b/app/javascript/mastodon/locales/he.json
@@ -202,7 +202,7 @@
   "dismissable_banner.community_timeline": "אלו הם החצרוצים הציבוריים האחרונים מהמשתמשים על שרת {domain}.",
   "dismissable_banner.dismiss": "בטל",
   "dismissable_banner.explore_links": "אלו הקישורים האחרונים ששותפו על ידי משתמשים ששרת זה רואה ברשת המבוזרת כרגע.",
-  "dismissable_banner.explore_statuses": "ההודעות האלו, משרת זה ואחרים ברשת המבוזרת, צוברים חשיפה היום. הודעות חדשות יותר עם יותר הדהודים וחיבובים מדורגות גבוה יותר.",
+  "dismissable_banner.explore_statuses": "אלו הודעות משרת זה ואחרים ברשת המבוזרת שצוברות חשיפה היום. הודעות חדשות יותר עם יותר הדהודים וחיבובים מדורגות גבוה יותר.",
   "dismissable_banner.explore_tags": "התגיות האלו, משרת זה ואחרים ברשת המבוזרת, צוברות חשיפה כעת.",
   "dismissable_banner.public_timeline": "אלו ההודעות האחרונות שהתקבלו מהמשתמשים שנעקבים על ידי משתמשים מ־{domain}.",
   "embed.instructions": "ניתן להטמיע את ההודעה הזו באתרך ע\"י העתקת הקוד שלהלן.",
@@ -630,7 +630,7 @@
   "status.edited": "נערך ב{date}",
   "status.edited_x_times": "נערך {count, plural, one {פעם {count}} other {{count} פעמים}}",
   "status.embed": "הטמעה",
-  "status.favourite": "מחובבת",
+  "status.favourite": "חיבוב",
   "status.filter": "סנן הודעה זו",
   "status.filtered": "סונן",
   "status.hide": "הסתרת חיצרוץ",
diff --git a/app/javascript/mastodon/locales/hr.json b/app/javascript/mastodon/locales/hr.json
index 4d751cdda7d8e9..cb1b201a123f61 100644
--- a/app/javascript/mastodon/locales/hr.json
+++ b/app/javascript/mastodon/locales/hr.json
@@ -1,5 +1,6 @@
 {
   "about.contact": "Kontakt:",
+  "about.domain_blocks.no_reason_available": "Razlog nije dostupan",
   "account.account_note_header": "Bilješka",
   "account.add_or_remove_from_list": "Dodaj ili ukloni s liste",
   "account.badges.bot": "Bot",
@@ -14,6 +15,7 @@
   "account.edit_profile": "Uredi profil",
   "account.enable_notifications": "Obavjesti me kada @{name} napravi objavu",
   "account.endorse": "Istakni na profilu",
+  "account.featured_tags.last_status_never": "Nema postova",
   "account.follow": "Prati",
   "account.followers": "Pratitelji",
   "account.followers.empty": "Nitko još ne prati korisnika/cu.",
@@ -21,13 +23,18 @@
   "account.following_counter": "{count, plural, one {{counter} praćeni} few{{counter} praćena} other {{counter} praćenih}}",
   "account.follows.empty": "Korisnik/ca još ne prati nikoga.",
   "account.follows_you": "Prati te",
+  "account.go_to_profile": "Idi na profil",
   "account.hide_reblogs": "Sakrij boostove od @{name}",
+  "account.in_memoriam": "U sjećanje.",
   "account.link_verified_on": "Vlasništvo ove poveznice provjereno je {date}",
   "account.locked_info": "Status privatnosti ovog računa postavljen je na zaključano. Vlasnik ručno pregledava tko ih može pratiti.",
   "account.media": "Medijski sadržaj",
   "account.mention": "Spomeni @{name}",
   "account.mute": "Utišaj @{name}",
+  "account.mute_notifications_short": "Utišaj obavijesti",
+  "account.mute_short": "Utišaj",
   "account.muted": "Utišano",
+  "account.open_original_page": "Otvori originalnu stranicu",
   "account.posts": "Objave",
   "account.posts_with_replies": "Objave i odgovori",
   "account.report": "Prijavi @{name}",
@@ -52,6 +59,7 @@
   "alert.unexpected.title": "Ups!",
   "announcement.announcement": "Najava",
   "attachments_list.unprocessed": "(neobrađeno)",
+  "audio.hide": "Sakrij audio",
   "autosuggest_hashtag.per_week": "{count} tjedno",
   "boost_modal.combo": "Možete pritisnuti {combo} kako biste preskočili ovo sljedeći put",
   "bundle_column_error.error.title": "Oh, ne!",
@@ -66,6 +74,7 @@
   "column.community": "Lokalna vremenska crta",
   "column.directory": "Pregledavanje profila",
   "column.domain_blocks": "Blokirane domene",
+  "column.favourites": "Favoriti",
   "column.follow_requests": "Zahtjevi za praćenje",
   "column.home": "Početna",
   "column.lists": "Liste",
@@ -86,6 +95,8 @@
   "community.column_settings.remote_only": "Samo udaljeno",
   "compose.language.change": "Promijeni jezik",
   "compose.language.search": "Pretraži jezike...",
+  "compose.published.open": "Otvori",
+  "compose.saved.body": "Post spremljen.",
   "compose_form.direct_message_warning_learn_more": "Saznajte više",
   "compose_form.encryption_warning": "Posts on Mastodon are not end-to-end encrypted. Do not share any dangerous information over Mastodon.",
   "compose_form.hashtag_warning": "This post won't be listed under any hashtag as it is unlisted. Only public posts can be searched by hashtag.",
@@ -179,6 +190,8 @@
   "errors.unexpected_crash.copy_stacktrace": "Kopiraj stacktrace u međuspremnik",
   "errors.unexpected_crash.report_issue": "Prijavi problem",
   "explore.search_results": "Rezultati pretrage",
+  "explore.suggested_follows": "Ljudi",
+  "explore.title": "Pretraži",
   "explore.trending_links": "Novosti",
   "explore.trending_statuses": "Objave",
   "explore.trending_tags": "Hashtagovi",
@@ -189,12 +202,17 @@
   "filter_modal.select_filter.subtitle": "Odaberite postojeću kategoriju ili stvorite novu",
   "filter_modal.select_filter.title": "Filtriraj ovu objavu",
   "filter_modal.title.status": "Filtriraj objavu",
+  "firehose.all": "Sve",
+  "firehose.local": "Ovaj server",
   "follow_request.authorize": "Autoriziraj",
   "follow_request.reject": "Odbij",
+  "footer.about": "O aplikaciji",
   "footer.get_app": "Preuzmi aplikaciju",
+  "footer.invite": "Pozovi ljude",
   "footer.keyboard_shortcuts": "Tipkovni prečaci",
   "footer.privacy_policy": "Pravila o zaštiti privatnosti",
   "footer.source_code": "Prikaz izvornog koda",
+  "footer.status": "Stanje",
   "generic.saved": "Spremljeno",
   "getting_started.heading": "Počnimo",
   "hashtag.column_header.tag_mode.all": "i {additional}",
@@ -212,7 +230,11 @@
   "home.column_settings.show_reblogs": "Pokaži boostove",
   "home.column_settings.show_replies": "Pokaži odgovore",
   "home.hide_announcements": "Sakrij najave",
+  "home.pending_critical_update.title": "Dostupno je kritično sigurnosno ažuriranje!",
   "home.show_announcements": "Prikaži najave",
+  "interaction_modal.login.action": "Odvedi me kući",
+  "interaction_modal.no_account_yet": "Nisi na Mastodonu?",
+  "interaction_modal.on_this_server": "Na ovom serveru",
   "intervals.full.days": "{number, plural, one {# dan} other {# dana}}",
   "intervals.full.hours": "{number, plural, one {# sat} few {# sata} other {# sati}}",
   "intervals.full.minutes": "{number, plural, one {# minuta} few {# minute} other {# minuta}}",
diff --git a/app/javascript/mastodon/locales/intl_provider.tsx b/app/javascript/mastodon/locales/intl_provider.tsx
index 4fa8b2247c7cb2..68d4fcbd965191 100644
--- a/app/javascript/mastodon/locales/intl_provider.tsx
+++ b/app/javascript/mastodon/locales/intl_provider.tsx
@@ -2,12 +2,14 @@ import { useEffect, useState } from 'react';
 
 import { IntlProvider as BaseIntlProvider } from 'react-intl';
 
+import { isProduction } from 'mastodon/utils/environment';
+
 import { getLocale, isLocaleLoaded } from './global_locale';
 import { loadLocale } from './load_locale';
 
 function onProviderError(error: unknown) {
   // Silent the error, like upstream does
-  if (process.env.NODE_ENV === 'production') return;
+  if (isProduction()) return;
 
   // This browser does not advertise Intl support for this locale, we only print a warning
   // As-per the spec, the browser should select the best matching locale
diff --git a/app/javascript/mastodon/locales/sl.json b/app/javascript/mastodon/locales/sl.json
index 3841237f47cc9a..63507be791c919 100644
--- a/app/javascript/mastodon/locales/sl.json
+++ b/app/javascript/mastodon/locales/sl.json
@@ -61,12 +61,12 @@
   "account.requested_follow": "{name} vam želi slediti",
   "account.share": "Deli profil osebe @{name}",
   "account.show_reblogs": "Pokaži izpostavitve osebe @{name}",
-  "account.statuses_counter": "{count, plural, one {{count} tut} two {{count} tuta} few {{count} tuti} other {{count} tutov}}",
+  "account.statuses_counter": "{count, plural, one {{count} objava} two {{count} objavi} few {{count} objave} other {{count} objav}}",
   "account.unblock": "Odblokiraj @{name}",
   "account.unblock_domain": "Odblokiraj domeno {domain}",
   "account.unblock_short": "Odblokiraj",
   "account.unendorse": "Ne vključi v profil",
-  "account.unfollow": "Prenehaj slediti",
+  "account.unfollow": "Ne sledi več",
   "account.unmute": "Odtišaj @{name}",
   "account.unmute_notifications_short": "Izklopi utišanje obvestil",
   "account.unmute_short": "Odtišaj",
@@ -185,7 +185,7 @@
   "confirmations.redraft.message": "Ali ste prepričani, da želite izbrisati ta status in ga preoblikovati? Vzljubi in izpostavitve bodo izgubljeni, odgovori na izvirno objavo pa bodo osiroteli.",
   "confirmations.reply.confirm": "Odgovori",
   "confirmations.reply.message": "Odgovarjanje bo prepisalo sporočilo, ki ga trenutno sestavljate. Ali ste prepričani, da želite nadaljevati?",
-  "confirmations.unfollow.confirm": "Prenehaj slediti",
+  "confirmations.unfollow.confirm": "Ne sledi več",
   "confirmations.unfollow.message": "Ali ste prepričani, da ne želite več slediti {name}?",
   "conversation.delete": "Izbriši pogovor",
   "conversation.mark_as_read": "Označi kot prebrano",
@@ -301,7 +301,7 @@
   "hashtag.counter_by_uses_today": "{count, plural, one {{counter} objava} two {{counter} objavi} few {{counter} objav} other {{counter} objav}}",
   "hashtag.follow": "Sledi ključniku",
   "hashtag.unfollow": "Nehaj slediti ključniku",
-  "hashtags.and_other": "…and {count, plural, one {} two {# več} few {# več}other {# več}}",
+  "hashtags.and_other": "…in še {count, plural, other {#}}",
   "home.actions.go_to_explore": "Poglejte, kaj je v trendu",
   "home.actions.go_to_suggestions": "Poiščite osebe, ki jim želite slediti",
   "home.column_settings.basic": "Osnovno",
diff --git a/app/javascript/mastodon/main.jsx b/app/javascript/mastodon/main.jsx
index cd73cb572e1d12..e7979d56a1c8c8 100644
--- a/app/javascript/mastodon/main.jsx
+++ b/app/javascript/mastodon/main.jsx
@@ -7,6 +7,8 @@ import * as perf from 'mastodon/performance';
 import ready from 'mastodon/ready';
 import { store } from 'mastodon/store';
 
+import { isProduction } from './utils/environment';
+
 /**
  * @returns {Promise<void>}
  */
@@ -21,7 +23,7 @@ function main() {
     root.render(<Mastodon {...props} />);
     store.dispatch(setupBrowserNotifications());
 
-    if (process.env.NODE_ENV === 'production' && me && 'serviceWorker' in navigator) {
+    if (isProduction() && me && 'serviceWorker' in navigator) {
       const { Workbox } = await import('workbox-window');
       const wb = new Workbox('/sw.js');
       /** @type {ServiceWorkerRegistration} */
diff --git a/app/javascript/mastodon/models/account.ts b/app/javascript/mastodon/models/account.ts
new file mode 100644
index 00000000000000..f20d2a2d3e1561
--- /dev/null
+++ b/app/javascript/mastodon/models/account.ts
@@ -0,0 +1,149 @@
+import type { RecordOf } from 'immutable';
+import { List, Record as ImmutableRecord } from 'immutable';
+
+import escapeTextContentForBrowser from 'escape-html';
+
+import type {
+  ApiAccountFieldJSON,
+  ApiAccountRoleJSON,
+  ApiAccountJSON,
+} from 'mastodon/api_types/accounts';
+import type { ApiCustomEmojiJSON } from 'mastodon/api_types/custom_emoji';
+import emojify from 'mastodon/features/emoji/emoji';
+import { unescapeHTML } from 'mastodon/utils/html';
+
+import { CustomEmojiFactory } from './custom_emoji';
+import type { CustomEmoji } from './custom_emoji';
+
+// AccountField
+interface AccountFieldShape extends Required<ApiAccountFieldJSON> {
+  name_emojified: string;
+  value_emojified: string;
+  value_plain: string | null;
+}
+
+type AccountField = RecordOf<AccountFieldShape>;
+
+const AccountFieldFactory = ImmutableRecord<AccountFieldShape>({
+  name: '',
+  value: '',
+  verified_at: null,
+  name_emojified: '',
+  value_emojified: '',
+  value_plain: null,
+});
+
+// AccountRole
+export type AccountRoleShape = ApiAccountRoleJSON;
+export type AccountRole = RecordOf<AccountRoleShape>;
+
+const AccountRoleFactory = ImmutableRecord<AccountRoleShape>({
+  color: '',
+  id: '',
+  name: '',
+});
+
+// Account
+export interface AccountShape
+  extends Required<
+    Omit<ApiAccountJSON, 'emojis' | 'fields' | 'roles' | 'moved'>
+  > {
+  emojis: List<CustomEmoji>;
+  fields: List<AccountField>;
+  roles: List<AccountRole>;
+  display_name_html: string;
+  note_emojified: string;
+  note_plain: string | null;
+  hidden: boolean;
+  moved: string | null;
+}
+
+export type Account = RecordOf<AccountShape>;
+
+export const accountDefaultValues: AccountShape = {
+  acct: '',
+  avatar: '',
+  avatar_static: '',
+  bot: false,
+  created_at: '',
+  discoverable: false,
+  display_name: '',
+  display_name_html: '',
+  emojis: List<CustomEmoji>(),
+  fields: List<AccountField>(),
+  group: false,
+  header: '',
+  header_static: '',
+  id: '',
+  last_status_at: '',
+  locked: false,
+  noindex: false,
+  note: '',
+  note_emojified: '',
+  note_plain: 'string',
+  roles: List<AccountRole>(),
+  uri: '',
+  url: '',
+  username: '',
+  followers_count: 0,
+  following_count: 0,
+  statuses_count: 0,
+  hidden: false,
+  suspended: false,
+  memorial: false,
+  limited: false,
+  moved: null,
+};
+
+const AccountFactory = ImmutableRecord<AccountShape>(accountDefaultValues);
+
+type EmojiMap = Record<string, ApiCustomEmojiJSON>;
+
+function makeEmojiMap(emojis: ApiCustomEmojiJSON[]) {
+  return emojis.reduce<EmojiMap>((obj, emoji) => {
+    obj[`:${emoji.shortcode}:`] = emoji;
+    return obj;
+  }, {});
+}
+
+function createAccountField(
+  jsonField: ApiAccountFieldJSON,
+  emojiMap: EmojiMap,
+) {
+  return AccountFieldFactory({
+    ...jsonField,
+    name_emojified: emojify(
+      escapeTextContentForBrowser(jsonField.name),
+      emojiMap,
+    ),
+    value_emojified: emojify(jsonField.value, emojiMap),
+    value_plain: unescapeHTML(jsonField.value),
+  });
+}
+
+export function createAccountFromServerJSON(serverJSON: ApiAccountJSON) {
+  const { moved, ...accountJSON } = serverJSON;
+
+  const emojiMap = makeEmojiMap(accountJSON.emojis);
+
+  const displayName =
+    accountJSON.display_name.trim().length === 0
+      ? accountJSON.username
+      : accountJSON.display_name;
+
+  return AccountFactory({
+    ...accountJSON,
+    moved: moved?.id,
+    fields: List(
+      serverJSON.fields.map((field) => createAccountField(field, emojiMap)),
+    ),
+    emojis: List(serverJSON.emojis.map((emoji) => CustomEmojiFactory(emoji))),
+    roles: List(serverJSON.roles?.map((role) => AccountRoleFactory(role))),
+    display_name_html: emojify(
+      escapeTextContentForBrowser(displayName),
+      emojiMap,
+    ),
+    note_emojified: emojify(accountJSON.note, emojiMap),
+    note_plain: unescapeHTML(accountJSON.note),
+  });
+}
diff --git a/app/javascript/mastodon/models/custom_emoji.ts b/app/javascript/mastodon/models/custom_emoji.ts
new file mode 100644
index 00000000000000..76479f3aebf54e
--- /dev/null
+++ b/app/javascript/mastodon/models/custom_emoji.ts
@@ -0,0 +1,15 @@
+import type { RecordOf } from 'immutable';
+import { Record } from 'immutable';
+
+import type { ApiCustomEmojiJSON } from 'mastodon/api_types/custom_emoji';
+
+type CustomEmojiShape = Required<ApiCustomEmojiJSON>; // no changes from server shape
+export type CustomEmoji = RecordOf<CustomEmojiShape>;
+
+export const CustomEmojiFactory = Record<CustomEmojiShape>({
+  shortcode: '',
+  static_url: '',
+  url: '',
+  category: '',
+  visible_in_picker: false,
+});
diff --git a/app/javascript/mastodon/models/relationship.ts b/app/javascript/mastodon/models/relationship.ts
new file mode 100644
index 00000000000000..115b2787382a88
--- /dev/null
+++ b/app/javascript/mastodon/models/relationship.ts
@@ -0,0 +1,29 @@
+import type { RecordOf } from 'immutable';
+import { Record } from 'immutable';
+
+import type { ApiRelationshipJSON } from 'mastodon/api_types/relationships';
+
+type RelationshipShape = Required<ApiRelationshipJSON>; // no changes from server shape
+export type Relationship = RecordOf<RelationshipShape>;
+
+const RelationshipFactory = Record<RelationshipShape>({
+  blocked_by: false,
+  blocking: false,
+  domain_blocking: false,
+  endorsed: false,
+  followed_by: false,
+  following: false,
+  id: '',
+  languages: null,
+  muting_notifications: false,
+  muting: false,
+  note: '',
+  notifying: false,
+  requested_by: false,
+  requested: false,
+  showing_reblogs: false,
+});
+
+export function createRelationship(attributes: Partial<RelationshipShape>) {
+  return RelationshipFactory(attributes);
+}
diff --git a/app/javascript/mastodon/performance.js b/app/javascript/mastodon/performance.js
index 42849c82b10378..3bca95e85e63d6 100644
--- a/app/javascript/mastodon/performance.js
+++ b/app/javascript/mastodon/performance.js
@@ -5,7 +5,9 @@
 
 import * as marky from 'marky';
 
-if (process.env.NODE_ENV === 'development') {
+import { isDevelopment } from './utils/environment';
+
+if (isDevelopment()) {
   if (typeof performance !== 'undefined' && performance.setResourceTimingBufferSize) {
     // Increase Firefox's performance entry limit; otherwise it's capped to 150.
     // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1331135
@@ -18,13 +20,13 @@ if (process.env.NODE_ENV === 'development') {
 }
 
 export function start(name) {
-  if (process.env.NODE_ENV === 'development') {
+  if (isDevelopment()) {
     marky.mark(name);
   }
 }
 
 export function stop(name) {
-  if (process.env.NODE_ENV === 'development') {
+  if (isDevelopment()) {
     marky.stop(name);
   }
 }
diff --git a/app/javascript/mastodon/polyfills/base_polyfills.ts b/app/javascript/mastodon/polyfills/base_polyfills.ts
deleted file mode 100644
index 71565236cd00c3..00000000000000
--- a/app/javascript/mastodon/polyfills/base_polyfills.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-import 'core-js/features/object/assign';
-import 'core-js/features/object/values';
-import 'core-js/features/symbol';
-import 'core-js/features/promise/finally';
-import { decode as decodeBase64 } from '../utils/base64';
-
-if (!Object.hasOwn(HTMLCanvasElement.prototype, 'toBlob')) {
-  const BASE64_MARKER = ';base64,';
-
-  Object.defineProperty(HTMLCanvasElement.prototype, 'toBlob', {
-    value: function (
-      this: HTMLCanvasElement,
-      callback: BlobCallback,
-      type = 'image/png',
-      quality: unknown,
-    ) {
-      const dataURL: string = this.toDataURL(type, quality);
-      let data;
-
-      if (dataURL.includes(BASE64_MARKER)) {
-        const [, base64] = dataURL.split(BASE64_MARKER);
-        data = decodeBase64(base64);
-      } else {
-        [, data] = dataURL.split(',');
-      }
-
-      callback(new Blob([data], { type }));
-    },
-  });
-}
diff --git a/app/javascript/mastodon/polyfills/extra_polyfills.ts b/app/javascript/mastodon/polyfills/extra_polyfills.ts
index e6c69de8b557b7..a8d5530c5fcb6a 100644
--- a/app/javascript/mastodon/polyfills/extra_polyfills.ts
+++ b/app/javascript/mastodon/polyfills/extra_polyfills.ts
@@ -1,2 +1 @@
-import 'abortcontroller-polyfill/dist/abortcontroller-polyfill-only';
 import 'requestidlecallback';
diff --git a/app/javascript/mastodon/polyfills/index.ts b/app/javascript/mastodon/polyfills/index.ts
index e166c09d0e8b23..431c5b0f30f350 100644
--- a/app/javascript/mastodon/polyfills/index.ts
+++ b/app/javascript/mastodon/polyfills/index.ts
@@ -4,39 +4,18 @@
 
 import { loadIntlPolyfills } from './intl';
 
-function importBasePolyfills() {
-  return import(/* webpackChunkName: "base_polyfills" */ './base_polyfills');
-}
-
 function importExtraPolyfills() {
   return import(/* webpackChunkName: "extra_polyfills" */ './extra_polyfills');
 }
 
 export function loadPolyfills() {
-  const needsBasePolyfills = !(
-    'toBlob' in HTMLCanvasElement.prototype &&
-    'assign' in Object &&
-    'values' in Object &&
-    'Symbol' in window &&
-    'finally' in Promise.prototype
-  );
-
-  // Latest version of Firefox and Safari do not have IntersectionObserver.
-  // Edge does not have requestIdleCallback.
+  // Safari does not have requestIdleCallback.
   // This avoids shipping them all the polyfills.
-  /* eslint-disable @typescript-eslint/no-unnecessary-condition -- those properties might not exist in old browsers, even if they are always here in types */
-  const needsExtraPolyfills = !(
-    window.AbortController &&
-    window.IntersectionObserver &&
-    window.IntersectionObserverEntry &&
-    'isIntersecting' in IntersectionObserverEntry.prototype &&
-    window.requestIdleCallback
-  );
-  /* eslint-enable @typescript-eslint/no-unnecessary-condition */
+  const needsExtraPolyfills = !window.requestIdleCallback;
 
   return Promise.all([
     loadIntlPolyfills(),
-    needsBasePolyfills && importBasePolyfills(),
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition -- those properties might not exist in old browsers, even if they are always here in types
     needsExtraPolyfills && importExtraPolyfills(),
   ]);
 }
diff --git a/app/javascript/mastodon/reducers/accounts.js b/app/javascript/mastodon/reducers/accounts.js
deleted file mode 100644
index 76122cc63baa9f..00000000000000
--- a/app/javascript/mastodon/reducers/accounts.js
+++ /dev/null
@@ -1,39 +0,0 @@
-import { Map as ImmutableMap, fromJS } from 'immutable';
-
-import { ACCOUNT_REVEAL } from 'mastodon/actions/accounts';
-import { ACCOUNT_IMPORT, ACCOUNTS_IMPORT } from 'mastodon/actions/importer';
-
-const initialState = ImmutableMap();
-
-const normalizeAccount = (state, account) => {
-  account = { ...account };
-
-  delete account.followers_count;
-  delete account.following_count;
-  delete account.statuses_count;
-
-  account.hidden = state.getIn([account.id, 'hidden']) === false ? false : account.limited;
-
-  return state.set(account.id, fromJS(account));
-};
-
-const normalizeAccounts = (state, accounts) => {
-  accounts.forEach(account => {
-    state = normalizeAccount(state, account);
-  });
-
-  return state;
-};
-
-export default function accounts(state = initialState, action) {
-  switch(action.type) {
-  case ACCOUNT_IMPORT:
-    return normalizeAccount(state, action.account);
-  case ACCOUNTS_IMPORT:
-    return normalizeAccounts(state, action.accounts);
-  case ACCOUNT_REVEAL:
-    return state.setIn([action.id, 'hidden'], false);
-  default:
-    return state;
-  }
-}
diff --git a/app/javascript/mastodon/reducers/accounts.ts b/app/javascript/mastodon/reducers/accounts.ts
new file mode 100644
index 00000000000000..f7270eb60a574a
--- /dev/null
+++ b/app/javascript/mastodon/reducers/accounts.ts
@@ -0,0 +1,84 @@
+import { Map as ImmutableMap } from 'immutable';
+
+import type { Reducer } from 'redux';
+
+import {
+  followAccountSuccess,
+  unfollowAccountSuccess,
+  importAccounts,
+  revealAccount,
+} from 'mastodon/actions/accounts_typed';
+import type { ApiAccountJSON } from 'mastodon/api_types/accounts';
+import { me } from 'mastodon/initial_state';
+import type { Account } from 'mastodon/models/account';
+import { createAccountFromServerJSON } from 'mastodon/models/account';
+
+const initialState = ImmutableMap<string, Account>();
+
+const normalizeAccount = (
+  state: typeof initialState,
+  account: ApiAccountJSON,
+) => {
+  return state.set(
+    account.id,
+    createAccountFromServerJSON(account).set(
+      'hidden',
+      state.get(account.id)?.hidden === false
+        ? false
+        : account.limited || false,
+    ),
+  );
+};
+
+const normalizeAccounts = (
+  state: typeof initialState,
+  accounts: ApiAccountJSON[],
+) => {
+  accounts.forEach((account) => {
+    state = normalizeAccount(state, account);
+  });
+
+  return state;
+};
+
+function getCurrentUser() {
+  if (!me)
+    throw new Error(
+      'No current user (me) defined when calling `accountsReducer`',
+    );
+
+  return me;
+}
+
+export const accountsReducer: Reducer<typeof initialState> = (
+  state = initialState,
+  action,
+) => {
+  if (revealAccount.match(action))
+    return state.setIn([action.payload.id, 'hidden'], false);
+  else if (importAccounts.match(action))
+    return normalizeAccounts(state, action.payload.accounts);
+  else if (followAccountSuccess.match(action)) {
+    return state
+      .update(
+        action.payload.relationship.id,
+        (account) => account?.update('followers_count', (n) => n + 1),
+      )
+      .update(
+        getCurrentUser(),
+        (account) => account?.update('following_count', (n) => n + 1),
+      );
+  } else if (unfollowAccountSuccess.match(action))
+    return state
+      .update(
+        action.payload.relationship.id,
+        (account) =>
+          account?.update('followers_count', (n) => Math.max(0, n - 1)),
+      )
+      .update(
+        getCurrentUser(),
+        (account) =>
+          account?.update('following_count', (n) => Math.max(0, n - 1)),
+      );
+  else return state;
+};
diff --git a/app/javascript/mastodon/reducers/accounts_counters.js b/app/javascript/mastodon/reducers/accounts_counters.js
deleted file mode 100644
index eb7878deb9a632..00000000000000
--- a/app/javascript/mastodon/reducers/accounts_counters.js
+++ /dev/null
@@ -1,49 +0,0 @@
-import { Map as ImmutableMap, fromJS } from 'immutable';
-
-import { me } from 'mastodon/initial_state';
-
-import {
-  ACCOUNT_FOLLOW_SUCCESS,
-  ACCOUNT_UNFOLLOW_SUCCESS,
-} from '../actions/accounts';
-import { ACCOUNT_IMPORT, ACCOUNTS_IMPORT } from '../actions/importer';
-
-const normalizeAccount = (state, account) => state.set(account.id, fromJS({
-  followers_count: account.followers_count,
-  following_count: account.following_count,
-  statuses_count: account.statuses_count,
-}));
-
-const normalizeAccounts = (state, accounts) => {
-  accounts.forEach(account => {
-    state = normalizeAccount(state, account);
-  });
-
-  return state;
-};
-
-const incrementFollowers = (state, accountId) =>
-  state.updateIn([accountId, 'followers_count'], num => num + 1)
-    .updateIn([me, 'following_count'], num => num + 1);
-
-const decrementFollowers = (state, accountId) =>
-  state.updateIn([accountId, 'followers_count'], num => Math.max(0, num - 1))
-    .updateIn([me, 'following_count'], num => Math.max(0, num - 1));
-
-const initialState = ImmutableMap();
-
-export default function accountsCounters(state = initialState, action) {
-  switch(action.type) {
-  case ACCOUNT_IMPORT:
-    return normalizeAccount(state, action.account);
-  case ACCOUNTS_IMPORT:
-    return normalizeAccounts(state, action.accounts);
-  case ACCOUNT_FOLLOW_SUCCESS:
-    return action.alreadyFollowing ? state :
-      incrementFollowers(state, action.relationship.id);
-  case ACCOUNT_UNFOLLOW_SUCCESS:
-    return decrementFollowers(state, action.relationship.id);
-  default:
-    return state;
-  }
-}
diff --git a/app/javascript/mastodon/reducers/accounts_map.js b/app/javascript/mastodon/reducers/accounts_map.js
index fca0e3ce1e3bc8..d5ecad7dbfaddf 100644
--- a/app/javascript/mastodon/reducers/accounts_map.js
+++ b/app/javascript/mastodon/reducers/accounts_map.js
@@ -1,7 +1,7 @@
 import { Map as ImmutableMap } from 'immutable';
 
 import { ACCOUNT_LOOKUP_FAIL } from '../actions/accounts';
-import { ACCOUNT_IMPORT, ACCOUNTS_IMPORT } from '../actions/importer';
+import { importAccounts } from '../actions/accounts_typed';
 
 export const normalizeForLookup = str => str.toLowerCase();
 
@@ -11,10 +11,8 @@ export default function accountsMap(state = initialState, action) {
   switch(action.type) {
   case ACCOUNT_LOOKUP_FAIL:
     return action.error?.response?.status === 404 ? state.set(normalizeForLookup(action.acct), null) : state;
-  case ACCOUNT_IMPORT:
-    return state.set(normalizeForLookup(action.account.acct), action.account.id);
-  case ACCOUNTS_IMPORT:
-    return state.withMutations(map => action.accounts.forEach(account => map.set(normalizeForLookup(account.acct), account.id)));
+  case importAccounts.type:
+    return state.withMutations(map => action.payload.accounts.forEach(account => map.set(normalizeForLookup(account.acct), account.id)));
   default:
     return state;
   }
diff --git a/app/javascript/mastodon/reducers/contexts.js b/app/javascript/mastodon/reducers/contexts.js
index 32e194dd42568c..f7d7419a4e3ab9 100644
--- a/app/javascript/mastodon/reducers/contexts.js
+++ b/app/javascript/mastodon/reducers/contexts.js
@@ -1,8 +1,8 @@
 import { Map as ImmutableMap, List as ImmutableList } from 'immutable';
 
 import {
-  ACCOUNT_BLOCK_SUCCESS,
-  ACCOUNT_MUTE_SUCCESS,
+  blockAccountSuccess,
+  muteAccountSuccess,
 } from '../actions/accounts';
 import { CONTEXT_FETCH_SUCCESS } from '../actions/statuses';
 import { TIMELINE_DELETE, TIMELINE_UPDATE } from '../actions/timelines';
@@ -92,9 +92,9 @@ const updateContext = (state, status) => {
 
 export default function replies(state = initialState, action) {
   switch(action.type) {
-  case ACCOUNT_BLOCK_SUCCESS:
-  case ACCOUNT_MUTE_SUCCESS:
-    return filterContexts(state, action.relationship, action.statuses);
+  case blockAccountSuccess.type:
+  case muteAccountSuccess.type:
+    return filterContexts(state, action.payload.relationship, action.payload.statuses);
   case CONTEXT_FETCH_SUCCESS:
     return normalizeContext(state, action.id, action.ancestors, action.descendants);
   case TIMELINE_DELETE:
diff --git a/app/javascript/mastodon/reducers/conversations.js b/app/javascript/mastodon/reducers/conversations.js
index 247e8a5977cd5c..3e99e680e3e7a2 100644
--- a/app/javascript/mastodon/reducers/conversations.js
+++ b/app/javascript/mastodon/reducers/conversations.js
@@ -1,7 +1,7 @@
 import { Map as ImmutableMap, List as ImmutableList } from 'immutable';
 
-import { ACCOUNT_BLOCK_SUCCESS, ACCOUNT_MUTE_SUCCESS } from 'mastodon/actions/accounts';
-import { DOMAIN_BLOCK_SUCCESS } from 'mastodon/actions/domain_blocks';
+import { blockAccountSuccess, muteAccountSuccess } from 'mastodon/actions/accounts';
+import { blockDomainSuccess } from 'mastodon/actions/domain_blocks';
 
 import {
   CONVERSATIONS_MOUNT,
@@ -105,11 +105,11 @@ export default function conversations(state = initialState, action) {
 
       return item;
     }));
-  case ACCOUNT_BLOCK_SUCCESS:
-  case ACCOUNT_MUTE_SUCCESS:
-    return filterConversations(state, [action.relationship.id]);
-  case DOMAIN_BLOCK_SUCCESS:
-    return filterConversations(state, action.accounts);
+  case blockAccountSuccess.type:
+  case muteAccountSuccess.type:
+    return filterConversations(state, [action.payload.relationship.id]);
+  case blockDomainSuccess.type:
+    return filterConversations(state, action.payload.accounts);
   case CONVERSATIONS_DELETE_SUCCESS:
     return state.update('items', list => list.filterNot(item => item.get('id') === action.id));
   default:
diff --git a/app/javascript/mastodon/reducers/domain_lists.js b/app/javascript/mastodon/reducers/domain_lists.js
index 8cdd3ba3764e55..5f63c77f5d4200 100644
--- a/app/javascript/mastodon/reducers/domain_lists.js
+++ b/app/javascript/mastodon/reducers/domain_lists.js
@@ -3,7 +3,7 @@ import { Map as ImmutableMap, OrderedSet as ImmutableOrderedSet } from 'immutabl
 import {
   DOMAIN_BLOCKS_FETCH_SUCCESS,
   DOMAIN_BLOCKS_EXPAND_SUCCESS,
-  DOMAIN_UNBLOCK_SUCCESS,
+  unblockDomainSuccess
 } from '../actions/domain_blocks';
 
 const initialState = ImmutableMap({
@@ -18,8 +18,8 @@ export default function domainLists(state = initialState, action) {
     return state.setIn(['blocks', 'items'], ImmutableOrderedSet(action.domains)).setIn(['blocks', 'next'], action.next);
   case DOMAIN_BLOCKS_EXPAND_SUCCESS:
     return state.updateIn(['blocks', 'items'], set => set.union(action.domains)).setIn(['blocks', 'next'], action.next);
-  case DOMAIN_UNBLOCK_SUCCESS:
-    return state.updateIn(['blocks', 'items'], set => set.delete(action.domain));
+  case unblockDomainSuccess.type:
+    return state.updateIn(['blocks', 'items'], set => set.delete(action.payload.domain));
   default:
     return state;
   }
diff --git a/app/javascript/mastodon/reducers/index.ts b/app/javascript/mastodon/reducers/index.ts
index 722f04f3700d92..ecef63387377b5 100644
--- a/app/javascript/mastodon/reducers/index.ts
+++ b/app/javascript/mastodon/reducers/index.ts
@@ -3,8 +3,7 @@ import { Record as ImmutableRecord } from 'immutable';
 import { loadingBarReducer } from 'react-redux-loading-bar';
 import { combineReducers } from 'redux-immutable';
 
-import accounts from './accounts';
-import accounts_counters from './accounts_counters';
+import { accountsReducer } from './accounts';
 import accounts_map from './accounts_map';
 import alerts from './alerts';
 import announcements from './announcements';
@@ -32,7 +31,7 @@ import notifications from './notifications';
 import picture_in_picture from './picture_in_picture';
 import polls from './polls';
 import push_notifications from './push_notifications';
-import relationships from './relationships';
+import { relationshipsReducer } from './relationships';
 import search from './search';
 import server from './server';
 import settings from './settings';
@@ -55,11 +54,10 @@ const reducers = {
   user_lists,
   domain_lists,
   status_lists,
-  accounts,
-  accounts_counters,
+  accounts: accountsReducer,
   accounts_map,
   statuses,
-  relationships,
+  relationships: relationshipsReducer,
   settings,
   push_notifications,
   mutes,
diff --git a/app/javascript/mastodon/reducers/notifications.js b/app/javascript/mastodon/reducers/notifications.js
index 66870bec551a6b..4a7a822a35e951 100644
--- a/app/javascript/mastodon/reducers/notifications.js
+++ b/app/javascript/mastodon/reducers/notifications.js
@@ -1,12 +1,12 @@
 import { fromJS, Map as ImmutableMap, List as ImmutableList } from 'immutable';
 
-import { DOMAIN_BLOCK_SUCCESS } from 'mastodon/actions/domain_blocks';
+import { blockDomainSuccess } from 'mastodon/actions/domain_blocks';
 
 import {
-  ACCOUNT_BLOCK_SUCCESS,
-  ACCOUNT_MUTE_SUCCESS,
-  FOLLOW_REQUEST_AUTHORIZE_SUCCESS,
-  FOLLOW_REQUEST_REJECT_SUCCESS,
+  authorizeFollowRequestSuccess,
+  blockAccountSuccess,
+  muteAccountSuccess,
+  rejectFollowRequestSuccess,
 } from '../actions/accounts';
 import {
   focusApp,
@@ -16,7 +16,7 @@ import {
   MARKERS_FETCH_SUCCESS,
 } from '../actions/markers';
 import {
-  NOTIFICATIONS_UPDATE,
+  notificationsUpdate,
   NOTIFICATIONS_EXPAND_SUCCESS,
   NOTIFICATIONS_EXPAND_REQUEST,
   NOTIFICATIONS_EXPAND_FAIL,
@@ -274,19 +274,19 @@ export default function notifications(state = initialState, action) {
     return state.set('items', ImmutableList()).set('pendingItems', ImmutableList()).set('hasMore', true);
   case NOTIFICATIONS_SCROLL_TOP:
     return updateTop(state, action.top);
-  case NOTIFICATIONS_UPDATE:
-    return normalizeNotification(state, action.notification, action.usePendingItems);
+  case notificationsUpdate.type:
+    return normalizeNotification(state, action.payload.notification, action.payload.usePendingItems);
   case NOTIFICATIONS_EXPAND_SUCCESS:
     return expandNormalizedNotifications(state, action.notifications, action.next, action.isLoadingMore, action.isLoadingRecent, action.usePendingItems);
-  case ACCOUNT_BLOCK_SUCCESS:
-    return filterNotifications(state, [action.relationship.id]);
-  case ACCOUNT_MUTE_SUCCESS:
-    return action.relationship.muting_notifications ? filterNotifications(state, [action.relationship.id]) : state;
-  case DOMAIN_BLOCK_SUCCESS:
-    return filterNotifications(state, action.accounts);
-  case FOLLOW_REQUEST_AUTHORIZE_SUCCESS:
-  case FOLLOW_REQUEST_REJECT_SUCCESS:
-    return filterNotifications(state, [action.id], 'follow_request');
+  case blockAccountSuccess.type:
+    return filterNotifications(state, [action.payload.relationship.id]);
+  case muteAccountSuccess.type:
+    return action.relationship.muting_notifications ? filterNotifications(state, [action.payload.relationship.id]) : state;
+  case blockDomainSuccess.type:
+    return filterNotifications(state, action.payload.accounts);
+  case authorizeFollowRequestSuccess.type:
+  case rejectFollowRequestSuccess.type:
+    return filterNotifications(state, [action.payload.id], 'follow_request');
   case NOTIFICATIONS_CLEAR:
     return state.set('items', ImmutableList()).set('pendingItems', ImmutableList()).set('hasMore', false);
   case TIMELINE_DELETE:
diff --git a/app/javascript/mastodon/reducers/relationships.js b/app/javascript/mastodon/reducers/relationships.js
deleted file mode 100644
index 32b4b4f371b209..00000000000000
--- a/app/javascript/mastodon/reducers/relationships.js
+++ /dev/null
@@ -1,88 +0,0 @@
-import { Map as ImmutableMap, fromJS } from 'immutable';
-
-import {
-  submitAccountNote,
-} from '../actions/account_notes';
-import {
-  ACCOUNT_FOLLOW_SUCCESS,
-  ACCOUNT_FOLLOW_REQUEST,
-  ACCOUNT_FOLLOW_FAIL,
-  ACCOUNT_UNFOLLOW_SUCCESS,
-  ACCOUNT_UNFOLLOW_REQUEST,
-  ACCOUNT_UNFOLLOW_FAIL,
-  ACCOUNT_BLOCK_SUCCESS,
-  ACCOUNT_UNBLOCK_SUCCESS,
-  ACCOUNT_MUTE_SUCCESS,
-  ACCOUNT_UNMUTE_SUCCESS,
-  ACCOUNT_PIN_SUCCESS,
-  ACCOUNT_UNPIN_SUCCESS,
-  RELATIONSHIPS_FETCH_SUCCESS,
-  FOLLOW_REQUEST_AUTHORIZE_SUCCESS,
-  FOLLOW_REQUEST_REJECT_SUCCESS,
-} from '../actions/accounts';
-import {
-  DOMAIN_BLOCK_SUCCESS,
-  DOMAIN_UNBLOCK_SUCCESS,
-} from '../actions/domain_blocks';
-import {
-  NOTIFICATIONS_UPDATE,
-} from '../actions/notifications';
-
-
-const normalizeRelationship = (state, relationship) => state.set(relationship.id, fromJS(relationship));
-
-const normalizeRelationships = (state, relationships) => {
-  relationships.forEach(relationship => {
-    state = normalizeRelationship(state, relationship);
-  });
-
-  return state;
-};
-
-const setDomainBlocking = (state, accounts, blocking) => {
-  return state.withMutations(map => {
-    accounts.forEach(id => {
-      map.setIn([id, 'domain_blocking'], blocking);
-    });
-  });
-};
-
-const initialState = ImmutableMap();
-
-export default function relationships(state = initialState, action) {
-  switch(action.type) {
-  case FOLLOW_REQUEST_AUTHORIZE_SUCCESS:
-    return state.setIn([action.id, 'followed_by'], true).setIn([action.id, 'requested_by'], false);
-  case FOLLOW_REQUEST_REJECT_SUCCESS:
-    return state.setIn([action.id, 'followed_by'], false).setIn([action.id, 'requested_by'], false);
-  case NOTIFICATIONS_UPDATE:
-    return action.notification.type === 'follow_request' ? state.setIn([action.notification.account.id, 'requested_by'], true) : state;
-  case ACCOUNT_FOLLOW_REQUEST:
-    return state.getIn([action.id, 'following']) ? state : state.setIn([action.id, action.locked ? 'requested' : 'following'], true);
-  case ACCOUNT_FOLLOW_FAIL:
-    return state.setIn([action.id, action.locked ? 'requested' : 'following'], false);
-  case ACCOUNT_UNFOLLOW_REQUEST:
-    return state.setIn([action.id, 'following'], false);
-  case ACCOUNT_UNFOLLOW_FAIL:
-    return state.setIn([action.id, 'following'], true);
-  case ACCOUNT_FOLLOW_SUCCESS:
-  case ACCOUNT_UNFOLLOW_SUCCESS:
-  case ACCOUNT_BLOCK_SUCCESS:
-  case ACCOUNT_UNBLOCK_SUCCESS:
-  case ACCOUNT_MUTE_SUCCESS:
-  case ACCOUNT_UNMUTE_SUCCESS:
-  case ACCOUNT_PIN_SUCCESS:
-  case ACCOUNT_UNPIN_SUCCESS:
-    return normalizeRelationship(state, action.relationship);
-  case RELATIONSHIPS_FETCH_SUCCESS:
-    return normalizeRelationships(state, action.relationships);
-  case submitAccountNote.fulfilled:
-    return normalizeRelationship(state, action.payload.relationship);
-  case DOMAIN_BLOCK_SUCCESS:
-    return setDomainBlocking(state, action.accounts, true);
-  case DOMAIN_UNBLOCK_SUCCESS:
-    return setDomainBlocking(state, action.accounts, false);
-  default:
-    return state;
-  }
-}
diff --git a/app/javascript/mastodon/reducers/relationships.ts b/app/javascript/mastodon/reducers/relationships.ts
new file mode 100644
index 00000000000000..2ba61839c7bffa
--- /dev/null
+++ b/app/javascript/mastodon/reducers/relationships.ts
@@ -0,0 +1,123 @@
+import { Map as ImmutableMap } from 'immutable';
+
+import { isFulfilled } from '@reduxjs/toolkit';
+import type { Reducer } from 'redux';
+
+import type { ApiRelationshipJSON } from 'mastodon/api_types/relationships';
+import type { Account } from 'mastodon/models/account';
+import { createRelationship } from 'mastodon/models/relationship';
+import type { Relationship } from 'mastodon/models/relationship';
+
+import { submitAccountNote } from '../actions/account_notes';
+import {
+  followAccountSuccess,
+  unfollowAccountSuccess,
+  authorizeFollowRequestSuccess,
+  rejectFollowRequestSuccess,
+  followAccountRequest,
+  followAccountFail,
+  unfollowAccountRequest,
+  unfollowAccountFail,
+  blockAccountSuccess,
+  unblockAccountSuccess,
+  muteAccountSuccess,
+  unmuteAccountSuccess,
+  pinAccountSuccess,
+  unpinAccountSuccess,
+  fetchRelationshipsSuccess,
+} from '../actions/accounts_typed';
+import {
+  blockDomainSuccess,
+  unblockDomainSuccess,
+} from '../actions/domain_blocks_typed';
+import { notificationsUpdate } from '../actions/notifications_typed';
+
+const initialState = ImmutableMap<string, Relationship>();
+type State = typeof initialState;
+
+const normalizeRelationship = (
+  state: State,
+  relationship: ApiRelationshipJSON,
+) => state.set(relationship.id, createRelationship(relationship));
+
+const normalizeRelationships = (
+  state: State,
+  relationships: ApiRelationshipJSON[],
+) => {
+  relationships.forEach((relationship) => {
+    state = normalizeRelationship(state, relationship);
+  });
+
+  return state;
+};
+
+const setDomainBlocking = (
+  state: State,
+  accounts: Account[],
+  blocking: boolean,
+) => {
+  return state.withMutations((map) => {
+    accounts.forEach((id) => {
+      map.setIn([id, 'domain_blocking'], blocking);
+    });
+  });
+};
+
+export const relationshipsReducer: Reducer<State> = (
+  state = initialState,
+  action,
+) => {
+  if (authorizeFollowRequestSuccess.match(action))
+    return state
+      .setIn([action.payload.id, 'followed_by'], true)
+      .setIn([action.payload.id, 'requested_by'], false);
+  else if (rejectFollowRequestSuccess.match(action))
+    return state
+      .setIn([action.payload.id, 'followed_by'], false)
+      .setIn([action.payload.id, 'requested_by'], false);
+  else if (notificationsUpdate.match(action))
+    return action.payload.notification.type === 'follow_request'
+      ? state.setIn(
+          [action.payload.notification.account.id, 'requested_by'],
+          true,
+        )
+      : state;
+  else if (followAccountRequest.match(action))
+    return state.getIn([action.payload.id, 'following'])
+      ? state
+      : state.setIn(
+          [
+            action.payload.id,
+            action.payload.locked ? 'requested' : 'following',
+          ],
+          true,
+        );
+  else if (followAccountFail.match(action))
+    return state.setIn(
+      [action.payload.id, action.payload.locked ? 'requested' : 'following'],
+      false,
+    );
+  else if (unfollowAccountRequest.match(action))
+    return state.setIn([action.payload.id, 'following'], false);
+  else if (unfollowAccountFail.match(action))
+    return state.setIn([action.payload.id, 'following'], true);
+  else if (
+    followAccountSuccess.match(action) ||
+    unfollowAccountSuccess.match(action) ||
+    blockAccountSuccess.match(action) ||
+    unblockAccountSuccess.match(action) ||
+    muteAccountSuccess.match(action) ||
+    unmuteAccountSuccess.match(action) ||
+    pinAccountSuccess.match(action) ||
+    unpinAccountSuccess.match(action) ||
+    isFulfilled(submitAccountNote)(action)
+  )
+    return normalizeRelationship(state, action.payload.relationship);
+  else if (fetchRelationshipsSuccess.match(action))
+    return normalizeRelationships(state, action.payload.relationships);
+  else if (blockDomainSuccess.match(action))
+    return setDomainBlocking(state, action.payload.accounts, true);
+  else if (unblockDomainSuccess.match(action))
+    return setDomainBlocking(state, action.payload.accounts, false);
+  else return state;
+};
diff --git a/app/javascript/mastodon/reducers/status_lists.js b/app/javascript/mastodon/reducers/status_lists.js
index 41cc07341c4969..6cb6a937bb915e 100644
--- a/app/javascript/mastodon/reducers/status_lists.js
+++ b/app/javascript/mastodon/reducers/status_lists.js
@@ -1,8 +1,8 @@
 import { Map as ImmutableMap, OrderedSet as ImmutableOrderedSet } from 'immutable';
 
 import {
-  ACCOUNT_BLOCK_SUCCESS,
-  ACCOUNT_MUTE_SUCCESS,
+  blockAccountSuccess,
+  muteAccountSuccess,
 } from '../actions/accounts';
 import {
   BOOKMARKED_STATUSES_FETCH_REQUEST,
@@ -142,9 +142,9 @@ export default function statusLists(state = initialState, action) {
     return prependOneToList(state, 'pins', action.status);
   case UNPIN_SUCCESS:
     return removeOneFromList(state, 'pins', action.status);
-  case ACCOUNT_BLOCK_SUCCESS:
-  case ACCOUNT_MUTE_SUCCESS:
-    return state.updateIn(['trending', 'items'], ImmutableOrderedSet(), list => list.filterNot(statusId => action.statuses.getIn([statusId, 'account']) === action.relationship.id));
+  case blockAccountSuccess.type:
+  case muteAccountSuccess.type:
+    return state.updateIn(['trending', 'items'], ImmutableOrderedSet(), list => list.filterNot(statusId => action.payload.statuses.getIn([statusId, 'account']) === action.payload.relationship.id));
   default:
     return state;
   }
diff --git a/app/javascript/mastodon/reducers/suggestions.js b/app/javascript/mastodon/reducers/suggestions.js
index ce1bcc774064dc..0f224ff4b94f34 100644
--- a/app/javascript/mastodon/reducers/suggestions.js
+++ b/app/javascript/mastodon/reducers/suggestions.js
@@ -1,7 +1,7 @@
 import { Map as ImmutableMap, List as ImmutableList, fromJS } from 'immutable';
 
-import { ACCOUNT_BLOCK_SUCCESS, ACCOUNT_MUTE_SUCCESS } from 'mastodon/actions/accounts';
-import { DOMAIN_BLOCK_SUCCESS } from 'mastodon/actions/domain_blocks';
+import { blockAccountSuccess, muteAccountSuccess } from 'mastodon/actions/accounts';
+import { blockDomainSuccess } from 'mastodon/actions/domain_blocks';
 
 import {
   SUGGESTIONS_FETCH_REQUEST,
@@ -29,11 +29,11 @@ export default function suggestionsReducer(state = initialState, action) {
     return state.set('isLoading', false);
   case SUGGESTIONS_DISMISS:
     return state.update('items', list => list.filterNot(x => x.account === action.id));
-  case ACCOUNT_BLOCK_SUCCESS:
-  case ACCOUNT_MUTE_SUCCESS:
-    return state.update('items', list => list.filterNot(x => x.account === action.relationship.id));
-  case DOMAIN_BLOCK_SUCCESS:
-    return state.update('items', list => list.filterNot(x => action.accounts.includes(x.account)));
+  case blockAccountSuccess.type:
+  case muteAccountSuccess.type:
+    return state.update('items', list => list.filterNot(x => x.account === action.payload.relationship.id));
+  case blockDomainSuccess.type:
+    return state.update('items', list => list.filterNot(x => action.payload.accounts.includes(x.account)));
   default:
     return state;
   }
diff --git a/app/javascript/mastodon/reducers/timelines.js b/app/javascript/mastodon/reducers/timelines.js
index cb3da50727a6b4..43dedd6e6d8cc8 100644
--- a/app/javascript/mastodon/reducers/timelines.js
+++ b/app/javascript/mastodon/reducers/timelines.js
@@ -1,9 +1,9 @@
 import { Map as ImmutableMap, List as ImmutableList, OrderedSet as ImmutableOrderedSet, fromJS } from 'immutable';
 
 import {
-  ACCOUNT_BLOCK_SUCCESS,
-  ACCOUNT_MUTE_SUCCESS,
-  ACCOUNT_UNFOLLOW_SUCCESS,
+  blockAccountSuccess,
+  muteAccountSuccess,
+  unfollowAccountSuccess
 } from '../actions/accounts';
 import {
   TIMELINE_UPDATE,
@@ -200,11 +200,11 @@ export default function timelines(state = initialState, action) {
     return deleteStatus(state, action.id, action.references, action.reblogOf);
   case TIMELINE_CLEAR:
     return clearTimeline(state, action.timeline);
-  case ACCOUNT_BLOCK_SUCCESS:
-  case ACCOUNT_MUTE_SUCCESS:
-    return filterTimelines(state, action.relationship, action.statuses);
-  case ACCOUNT_UNFOLLOW_SUCCESS:
-    return filterTimeline('home', state, action.relationship, action.statuses);
+  case blockAccountSuccess.type:
+  case muteAccountSuccess.type:
+    return filterTimelines(state, action.payload.relationship, action.payload.statuses);
+  case unfollowAccountSuccess.type:
+    return filterTimeline('home', state, action.payload.relationship, action.payload.statuses);
   case TIMELINE_SCROLL_TOP:
     return updateTop(state, action.timeline, action.top);
   case TIMELINE_CONNECT:
diff --git a/app/javascript/mastodon/reducers/user_lists.js b/app/javascript/mastodon/reducers/user_lists.js
index 089899398ed872..2f17fed5fdb64a 100644
--- a/app/javascript/mastodon/reducers/user_lists.js
+++ b/app/javascript/mastodon/reducers/user_lists.js
@@ -33,8 +33,8 @@ import {
   FOLLOW_REQUESTS_EXPAND_REQUEST,
   FOLLOW_REQUESTS_EXPAND_SUCCESS,
   FOLLOW_REQUESTS_EXPAND_FAIL,
-  FOLLOW_REQUEST_AUTHORIZE_SUCCESS,
-  FOLLOW_REQUEST_REJECT_SUCCESS,
+  authorizeFollowRequestSuccess,
+  rejectFollowRequestSuccess,
 } from '../actions/accounts';
 import {
   BLOCKS_FETCH_REQUEST,
@@ -66,11 +66,7 @@ import {
   MUTES_EXPAND_SUCCESS,
   MUTES_EXPAND_FAIL,
 } from '../actions/mutes';
-import {
-  NOTIFICATIONS_UPDATE,
-} from '../actions/notifications';
-
-
+import { notificationsUpdate } from '../actions/notifications';
 
 const initialListState = ImmutableMap({
   next: null,
@@ -163,8 +159,8 @@ export default function userLists(state = initialState, action) {
   case FAVOURITES_FETCH_FAIL:
   case FAVOURITES_EXPAND_FAIL:
     return state.setIn(['favourited_by', action.id, 'isLoading'], false);
-  case NOTIFICATIONS_UPDATE:
-    return action.notification.type === 'follow_request' ? normalizeFollowRequest(state, action.notification) : state;
+  case notificationsUpdate.type:
+    return action.payload.notification.type === 'follow_request' ? normalizeFollowRequest(state, action.payload.notification) : state;
   case FOLLOW_REQUESTS_FETCH_SUCCESS:
     return normalizeList(state, ['follow_requests'], action.accounts, action.next);
   case FOLLOW_REQUESTS_EXPAND_SUCCESS:
@@ -175,9 +171,9 @@ export default function userLists(state = initialState, action) {
   case FOLLOW_REQUESTS_FETCH_FAIL:
   case FOLLOW_REQUESTS_EXPAND_FAIL:
     return state.setIn(['follow_requests', 'isLoading'], false);
-  case FOLLOW_REQUEST_AUTHORIZE_SUCCESS:
-  case FOLLOW_REQUEST_REJECT_SUCCESS:
-    return state.updateIn(['follow_requests', 'items'], list => list.filterNot(item => item === action.id));
+  case authorizeFollowRequestSuccess.type:
+  case rejectFollowRequestSuccess.type:
+    return state.updateIn(['follow_requests', 'items'], list => list.filterNot(item => item === action.payload.id));
   case BLOCKS_FETCH_SUCCESS:
     return normalizeList(state, ['blocks'], action.accounts, action.next);
   case BLOCKS_EXPAND_SUCCESS:
diff --git a/app/javascript/mastodon/selectors/accounts.ts b/app/javascript/mastodon/selectors/accounts.ts
new file mode 100644
index 00000000000000..66193136c45012
--- /dev/null
+++ b/app/javascript/mastodon/selectors/accounts.ts
@@ -0,0 +1,47 @@
+import { Record as ImmutableRecord } from 'immutable';
+import { createSelector } from 'reselect';
+
+import { accountDefaultValues } from 'mastodon/models/account';
+import type { Account, AccountShape } from 'mastodon/models/account';
+import type { Relationship } from 'mastodon/models/relationship';
+import type { RootState } from 'mastodon/store';
+
+const getAccountBase = (state: RootState, id: string) =>
+  state.accounts.get(id, null);
+
+const getAccountRelationship = (state: RootState, id: string) =>
+  state.relationships.get(id, null);
+
+const getAccountMoved = (state: RootState, id: string) => {
+  const movedToId = state.accounts.get(id)?.moved;
+
+  if (!movedToId) return undefined;
+
+  return state.accounts.get(movedToId);
+};
+
+interface FullAccountShape extends Omit<AccountShape, 'moved'> {
+  relationship: Relationship | null;
+  moved: Account | null;
+}
+
+const FullAccountFactory = ImmutableRecord<FullAccountShape>({
+  ...accountDefaultValues,
+  moved: null,
+  relationship: null,
+});
+
+export function makeGetAccount() {
+  return createSelector(
+    [getAccountBase, getAccountRelationship, getAccountMoved],
+    (base, relationship, moved) => {
+      if (base === null) {
+        return null;
+      }
+
+      return FullAccountFactory(base)
+        .set('relationship', relationship)
+        .set('moved', moved ?? null);
+    },
+  );
+}
diff --git a/app/javascript/mastodon/selectors/index.js b/app/javascript/mastodon/selectors/index.js
index 0968fb090b6cfd..8a07ba774d8e3c 100644
--- a/app/javascript/mastodon/selectors/index.js
+++ b/app/javascript/mastodon/selectors/index.js
@@ -5,23 +5,7 @@ import { toServerSideType } from 'mastodon/utils/filters';
 
 import { me } from '../initial_state';
 
-const getAccountBase         = (state, id) => state.getIn(['accounts', id], null);
-const getAccountCounters     = (state, id) => state.getIn(['accounts_counters', id], null);
-const getAccountRelationship = (state, id) => state.getIn(['relationships', id], null);
-const getAccountMoved        = (state, id) => state.getIn(['accounts', state.getIn(['accounts', id, 'moved'])]);
-
-export const makeGetAccount = () => {
-  return createSelector([getAccountBase, getAccountCounters, getAccountRelationship, getAccountMoved], (base, counters, relationship, moved) => {
-    if (base === null) {
-      return null;
-    }
-
-    return base.merge(counters).withMutations(map => {
-      map.set('relationship', relationship);
-      map.set('moved', moved);
-    });
-  });
-};
+export { makeGetAccount } from "./accounts";
 
 const getFilters = (state, { contextType }) => {
   if (!contextType) return null;
diff --git a/app/javascript/mastodon/store/store.ts b/app/javascript/mastodon/store/store.ts
index 63508856803810..9f43f58a43dfa4 100644
--- a/app/javascript/mastodon/store/store.ts
+++ b/app/javascript/mastodon/store/store.ts
@@ -35,6 +35,5 @@ export const store = configureStore({
 
 // Infer the `RootState` and `AppDispatch` types from the store itself
 export type RootState = ReturnType<typeof rootReducer>;
-// Inferred type: {posts: PostsState, comments: CommentsState, users: UsersState}
 export type AppDispatch = typeof store.dispatch;
 export type GetState = typeof store.getState;
diff --git a/app/javascript/mastodon/utils/environment.ts b/app/javascript/mastodon/utils/environment.ts
new file mode 100644
index 00000000000000..b6371499f63694
--- /dev/null
+++ b/app/javascript/mastodon/utils/environment.ts
@@ -0,0 +1,7 @@
+export function isDevelopment() {
+  return process.env.NODE_ENV === 'development';
+}
+
+export function isProduction() {
+  return process.env.NODE_ENV === 'production';
+}
diff --git a/app/javascript/types/resources.ts b/app/javascript/types/resources.ts
deleted file mode 100644
index f3901ad150c9b9..00000000000000
--- a/app/javascript/types/resources.ts
+++ /dev/null
@@ -1,55 +0,0 @@
-import type { Record } from 'immutable';
-
-type CustomEmoji = Record<{
-  shortcode: string;
-  static_url: string;
-  url: string;
-}>;
-
-type AccountField = Record<{
-  name: string;
-  value: string;
-  verified_at: string | null;
-}>;
-
-interface AccountApiResponseValues {
-  acct: string;
-  avatar: string;
-  avatar_static: string;
-  bot: boolean;
-  created_at: string;
-  discoverable: boolean;
-  display_name: string;
-  emojis: CustomEmoji[];
-  fields: AccountField[];
-  followers_count: number;
-  following_count: number;
-  group: boolean;
-  header: string;
-  header_static: string;
-  id: string;
-  last_status_at: string;
-  locked: boolean;
-  note: string;
-  statuses_count: number;
-  url: string;
-  uri: string;
-  username: string;
-}
-
-type NormalizedAccountField = Record<{
-  name_emojified: string;
-  value_emojified: string;
-  value_plain: string;
-}>;
-
-interface NormalizedAccountValues {
-  display_name_html: string;
-  fields: NormalizedAccountField[];
-  note_emojified: string;
-  note_plain: string;
-}
-
-export type Account = Record<
-  AccountApiResponseValues & NormalizedAccountValues
->;
diff --git a/app/lib/activitypub/parser/status_parser.rb b/app/lib/activitypub/parser/status_parser.rb
index 75b8f3d5c3f870..510f00f075d6de 100644
--- a/app/lib/activitypub/parser/status_parser.rb
+++ b/app/lib/activitypub/parser/status_parser.rb
@@ -53,7 +53,8 @@ def title
   end
 
   def created_at
-    @object['published']&.to_datetime
+    datetime = @object['published']&.to_datetime
+    datetime if datetime.present? && (0..9999).cover?(datetime.year)
   rescue ArgumentError
     nil
   end
diff --git a/app/services/fan_out_on_write_service.rb b/app/services/fan_out_on_write_service.rb
index 3b14a6748a7bf8..48167873e1058c 100644
--- a/app/services/fan_out_on_write_service.rb
+++ b/app/services/fan_out_on_write_service.rb
@@ -8,6 +8,7 @@ class FanOutOnWriteService < BaseService
   # @param [Hash] options
   # @option options [Boolean] update
   # @option options [Array<Integer>] silenced_account_ids
+  # @option options [Boolean] skip_notifications
   def call(status, options = {})
     @status    = status
     @account   = status.account
@@ -37,8 +38,11 @@ def check_race_condition!
 
   def fan_out_to_local_recipients!
     deliver_to_self!
-    notify_mentioned_accounts!
-    notify_about_update! if update?
+
+    unless @options[:skip_notifications]
+      notify_mentioned_accounts!
+      notify_about_update! if update?
+    end
 
     case @status.visibility.to_sym
     when :public, :unlisted, :private
diff --git a/app/workers/thread_resolve_worker.rb b/app/workers/thread_resolve_worker.rb
index 3206c45f6399e5..d4cefb3fdc0627 100644
--- a/app/workers/thread_resolve_worker.rb
+++ b/app/workers/thread_resolve_worker.rb
@@ -7,13 +7,18 @@ class ThreadResolveWorker
   sidekiq_options queue: 'pull', retry: 3
 
   def perform(child_status_id, parent_url, options = {})
-    child_status  = Status.find(child_status_id)
-    parent_status = FetchRemoteStatusService.new.call(parent_url, **options.deep_symbolize_keys)
+    child_status = Status.find(child_status_id)
+    return if child_status.in_reply_to_id.present?
+
+    parent_status = ActivityPub::TagManager.instance.uri_to_resource(parent_url, Status)
+    parent_status ||= FetchRemoteStatusService.new.call(parent_url, **options.deep_symbolize_keys)
 
     return if parent_status.nil?
 
     child_status.thread = parent_status
     child_status.save!
+
+    DistributionWorker.perform_async(child_status_id, { 'skip_notifications' => true }) if child_status.within_realtime_window?
   rescue ActiveRecord::RecordNotFound
     true
   end
diff --git a/babel.config.js b/babel.config.js
index f53e5918cbe089..9ced748a9615f7 100644
--- a/babel.config.js
+++ b/babel.config.js
@@ -7,8 +7,8 @@ module.exports = (api) => {
   };
 
   const envOptions = {
-    loose: true,
-    modules: false,
+    useBuiltIns: "usage",
+    corejs: { version: "3.30" },
     debug: false,
     include: [
       'transform-numeric-separator',
@@ -18,29 +18,14 @@ module.exports = (api) => {
     ],
   };
 
-  const config = {
-    presets: [
-      '@babel/preset-typescript',
-      ['@babel/react', reactOptions],
-      ['@babel/env', envOptions],
-    ],
-    plugins: [
-      ['formatjs'],
-      'preval',
-    ],
-    overrides: [
-      {
-        test: /tesseract\.js/,
-        presets: [
-          ['@babel/env', { ...envOptions, modules: 'commonjs' }],
-        ],
-      },
-    ],
-  };
+  const plugins = [
+    ['formatjs'],
+    'preval',
+  ];
 
   switch (env) {
   case 'production':
-    config.plugins.push(...[
+    plugins.push(...[
       'lodash',
       [
         'transform-react-remove-prop-types',
@@ -63,14 +48,33 @@ module.exports = (api) => {
       ],
     ]);
     break;
+
   case 'development':
     reactOptions.development = true;
     envOptions.debug = true;
-    break;
-  case 'test':
-    envOptions.modules = 'commonjs';
+
+    // We need Babel to not inject polyfills in dev, as this breaks `preval` files
+    envOptions.useBuiltIns = false;
+    envOptions.corejs = undefined;
     break;
   }
 
+  const config = {
+    presets: [
+      '@babel/preset-typescript',
+      ['@babel/react', reactOptions],
+      ['@babel/env', envOptions],
+    ],
+    plugins,
+    overrides: [
+      {
+        test: /tesseract\.js/,
+        presets: [
+          ['@babel/env', { ...envOptions, modules: 'commonjs' }],
+        ],
+      },
+    ],
+  };
+
   return config;
 };
diff --git a/config/initializers/devise.rb b/config/initializers/devise.rb
index 41d0ee25b78642..2c6099623db501 100644
--- a/config/initializers/devise.rb
+++ b/config/initializers/devise.rb
@@ -2,6 +2,15 @@
 
 require 'devise/strategies/authenticatable'
 
+# TODO: Remove this patch when this PR or similar is merged into Devise:
+# https://github.com/heartcombo/devise/pull/5645
+# We rely on ENV vars and not secrets/credentials, so the deprecation is just noise.
+class Devise::SecretKeyFinder
+  def find
+    @application.secret_key_base
+  end
+end
+
 Warden::Manager.after_set_user except: :fetch do |user, warden|
   session_id = warden.cookies.signed['_session_id'] || warden.raw_session['auth_id']
   session_id = user.activate_session(warden.request) unless user.session_activations.active?(session_id)
diff --git a/config/initializers/json_ld.rb b/config/initializers/json_ld.rb
deleted file mode 100644
index 3ed3c4b31a31bb..00000000000000
--- a/config/initializers/json_ld.rb
+++ /dev/null
@@ -1,4 +0,0 @@
-# frozen_string_literal: true
-
-require_relative '../../lib/json_ld/security'
-require_relative '../../lib/json_ld/identity'
diff --git a/lib/json_ld/identity.rb b/config/initializers/json_ld_identity.rb
similarity index 100%
rename from lib/json_ld/identity.rb
rename to config/initializers/json_ld_identity.rb
diff --git a/lib/json_ld/security.rb b/config/initializers/json_ld_security.rb
similarity index 100%
rename from lib/json_ld/security.rb
rename to config/initializers/json_ld_security.rb
diff --git a/config/locales/ar.yml b/config/locales/ar.yml
index f8c74207de7434..f43d1ad2a67bad 100644
--- a/config/locales/ar.yml
+++ b/config/locales/ar.yml
@@ -578,6 +578,7 @@ ar:
       total_reported: تقارير عنهم
       total_storage: الوسائط المُرفَقة
       totals_time_period_hint_html: المجموع المعروض في الأسفل يشمل بيانات منذ البداية.
+      unknown_instance: لا يوجد حاليا أي تسجيل لهذا النطاق على هذا الخادم.
     invites:
       deactivate_all: تعطيلها كافة
       filter:
@@ -1112,6 +1113,11 @@ ar:
       hint_html: شيء واحد آخر! نحن بحاجة إلى التأكّد من أنك إنسان (حتى نتمكن من تتفادي البريد المزعج!). حل رمز CAPTCHA أدناه وانقر فوق "متابعة".
       title: التحقق من الأمان
     confirmations:
+      awaiting_review: تمّ تأكيد عنوان بريدك الإلكتروني! موظفو %{domain} يعاينونَ تسجيلكَ حاليًا. ستتلقى بريدًا إلكترونيًا إن تَمّ قُبولك!
+      awaiting_review_title: التسجيل الخاص بك قيد المُعاينة
+      clicking_this_link: اضغط على هذا الرابط
+      login_link: تسجيل الدخول
+      proceed_to_login_html: يمكنكَ الآن الاستمرار إلى %{login_link}.
       wrong_email_hint: إذا كان عنوان البريد الإلكتروني هذا غير صحيح، يمكنك تغييره في إعدادات الحساب.
     delete_account: احذف الحساب
     delete_account_html: إن كنت ترغب في حذف حسابك يُمكنك <a href="%{path}">المواصلة هنا</a>. سوف يُطلَبُ منك التأكيد قبل الحذف.
diff --git a/config/locales/cy.yml b/config/locales/cy.yml
index baa6d31e3580ba..846ce41def5bd9 100644
--- a/config/locales/cy.yml
+++ b/config/locales/cy.yml
@@ -1,7 +1,7 @@
 ---
 cy:
   about:
-    about_mastodon_html: 'Rhwydwaith cymdeithasol y dyfodol: Dim hysbysebion, dim gwyliadwriaeth gorfforaethol, dylunio moesegol, a datganoli! Chi sy berchen eich data gyda Mastodon!'
+    about_mastodon_html: 'Rhwydwaith cymdeithasol y dyfodol: Dim hysbysebion, dim gwyliadwriaeth gorfforaethol, dylunio moesegol a datganoli! Chi sy berchen eich data gyda Mastodon!'
     contact_missing: Heb ei osodF
     contact_unavailable: Ddim yn berthnasol
     hosted_on: Mastodon wedi ei weinyddu ar %{domain}
@@ -1113,6 +1113,14 @@ cy:
       hint_html: Un peth arall! Mae angen i ni gadarnhau eich bod yn ddynol (mae hyn er mwyn i ni allu cadw'r sbam allan!). Datryswch y CAPTCHA isod a chliciwch "Parhau".
       title: Gwiriad diogelwch
     confirmations:
+      awaiting_review: Mae eich cyfeiriad e-bost wedi'i gadarnhau! Mae aelod o staff %{domain} wrthi'n adolygu'ch cofrestriad. Byddwch yn derbyn e-bost os ydyn nhw'n cymeradwyo eich cyfrif!
+      awaiting_review_title: Mae eich cofrestriad yn cael ei adolygu
+      clicking_this_link: clicio ar y ddolen hon
+      login_link: mewngofnodi
+      proceed_to_login_html: Gallwch nawr symud ymlaen i %{login_link}.
+      redirect_to_app_html: Dylech fod wedi cael eich ailgyfeirio i ap <strong>%{app_name}</strong>. Os na ddigwyddodd hynny, rhowch gynnig ar %{clicking_this_link} neu ewch eich hun i'r ap.
+      registration_complete: Mae eich cofrestriad ar %{domain} bellach wedi'i gwblhau!
+      welcome_title: Croeso, %{name}!
       wrong_email_hint: Os nad yw'r cyfeiriad e-bost hwnnw'n gywir, gallwch ei newid yng ngosodiadau'r cyfrif.
     delete_account: Dileu cyfrif
     delete_account_html: Os hoffech chi ddileu eich cyfrif, mae modd <a href="%{path}">parhau yma</a>. Bydd gofyn i chi gadarnhau.
diff --git a/config/locales/doorkeeper.hr.yml b/config/locales/doorkeeper.hr.yml
index cb48de313549e1..abf07ab723628a 100644
--- a/config/locales/doorkeeper.hr.yml
+++ b/config/locales/doorkeeper.hr.yml
@@ -35,8 +35,11 @@ hr:
         scopes: Odvojite opsege razmacima. Za korištenje zadanih opsega, ostavite prazno.
       index:
         application: Aplikacija
+        delete: Obriši
+        empty: Nemaš aplikacija.
         name: Ime
         new: Nova aplikacija
+        show: Prikaži
         title: Vaše aplikacije
       new:
         title: Nova aplikacija
@@ -60,6 +63,7 @@ hr:
       confirmations:
         revoke: Jeste li sigurni?
       index:
+        authorized_at: Autorizirano %{date}
         title: Vaše autorizirane aplikacije
     errors:
       messages:
@@ -88,6 +92,14 @@ hr:
       authorized_applications:
         destroy:
           notice: Aplikacija je opozvana.
+    grouped_scopes:
+      title:
+        favourites: Favoriti
+        filters: Filteri
+        follows: Praćeni
+        lists: Liste
+        search: Traži
+        statuses: Objave
     layouts:
       admin:
         nav:
@@ -95,6 +107,7 @@ hr:
       application:
         title: Traži se OAuth autorizacija
     scopes:
+      admin:read: pročitaj sve podatke na serveru
       follow: mijenjati odnose između računa
       read: čitati sve podatke Vašeg računa
       write: mijenjati sve podatke Vašeg računa
diff --git a/config/locales/doorkeeper.sl.yml b/config/locales/doorkeeper.sl.yml
index 8fe39bbf61f903..a613308b28afbf 100644
--- a/config/locales/doorkeeper.sl.yml
+++ b/config/locales/doorkeeper.sl.yml
@@ -4,7 +4,7 @@ sl:
     attributes:
       doorkeeper/application:
         name: Ime programa
-        redirect_uri: Preusmeritev URI
+        redirect_uri: URI za preusmeritev
         scopes: Obsegi
         website: Spletišče programa
     errors:
@@ -19,7 +19,7 @@ sl:
   doorkeeper:
     applications:
       buttons:
-        authorize: Overi
+        authorize: Odobri
         cancel: Prekliči
         destroy: Uniči
         edit: Uredi
@@ -55,23 +55,23 @@ sl:
         title: 'Program: %{name}'
     authorizations:
       buttons:
-        authorize: Overi
+        authorize: Odobri
         deny: Zavrni
       error:
         title: Prišlo je do napake
       new:
         prompt_html: "%{client_name} želi dovoljenje za dostop do vašega računa. Gre za zunanji program. <strong>Če mu ne zaupate, mu ne dodelite teh pravic.</strong>"
-        review_permissions: Preglej pravice
-        title: Potrebna je pooblastitev
+        review_permissions: Preglej dovoljenja
+        title: Potrebna je odobritev
       show:
-        title: Kopirajte to pooblastilno kodo in jo prilepite v program.
+        title: Kopirajte to odobritveno kodo in jo prilepite v program.
     authorized_applications:
       buttons:
         revoke: Prekliči
       confirmations:
         revoke: Ali ste prepričani?
       index:
-        authorized_at: Overjen(a) %{date}
+        authorized_at: Odobreno %{date}
         description_html: To so programi, ki lahko dostopajo do vašega računa prek vmesnika API. Če so na seznamu programi, ki jih ne prepoznate ali pa se čudno vedejo, lahko prekličete njihovo pravico do dostopa.
         last_used_at: Zadnjič uporabljeno %{date}
         never_used: Nikoli uporabljeno
@@ -80,14 +80,14 @@ sl:
         title: Vaši odobreni programi
     errors:
       messages:
-        access_denied: Lastnik virov ali strežnik pooblastil je zavrnil zahtevo.
+        access_denied: Lastnik virov ali odobritveni strežnik je zavrnil zahtevo.
         credential_flow_not_configured: Pretok geselskih pooblastil lastnika virov ni uspel, ker Doorkeeper.configure.resource_owner_from_credentials ni nastavljen.
-        invalid_client: Overitev odjemalca ni uspela zaradi neznanega odjemalca, zaradi nevključitve overitve odjemalca ali zaradi nepodprte metode overitve.
-        invalid_grant: Predložena odobritev za pooblastilo je neveljavna, potekla, preklicana, se ne ujema z URI preusmeritvijo, ki je uporabljena v zahtevi za pooblastilo ali je bila izdana drugemu odjemalcu.
+        invalid_client: Odobritev odjemalca ni uspela zaradi neznanega odjemalca, zaradi nevključitve odobritve odjemalca ali zaradi nepodprte metode odobritve.
+        invalid_grant: Predložena odobritev je neveljavna, je potekla, je preklicana, se ne ujema z URI-jem za preusmeritev uporabljenim v zahtevi za odobritev, ali pa je bila izdana drugemu odjemalcu.
         invalid_redirect_uri: URI za preusmeritev ni veljaven.
         invalid_request:
           missing_param: 'Zahtevani parameter manjka: %{value}.'
-          request_not_authorized: Zahtevo je potrebno overiti. Zahtevani parameter za overjanje zahteve manjka ali ni veljaven.
+          request_not_authorized: Zahtevo je potrebno odobriti. Zahtevani parameter za odobritev zahteve manjka ali ni veljaven.
           unknown: Zahtevku manjka zahtevani parameter, vključuje nepodprto vrednost parametra ali je nepravilno oblikovan.
         invalid_resource_owner: Predložene poverilnice lastnika virov niso veljavne ali pa lastnika virov ni mogoče najti
         invalid_scope: Zahtevani obseg je neveljaven, neznan ali nepravilen.
@@ -96,11 +96,11 @@ sl:
           revoked: Žeton za dostop je bil preklican
           unknown: Žeton za dostop je neveljaven
         resource_owner_authenticator_not_configured: Iskanje lastnika virov ni uspelo, ker Doorkeeper.configure.resource_owner_authenticator ni nastavljen.
-        server_error: Strežnik pooblastil je naletel na nepričakovano stanje, ki je preprečilo, da bi izpolnil zahtevo.
-        temporarily_unavailable: Strežnik pooblastil, zaradi začasne preobremenitve ali vzdrževanja, trenutno ne more obdelati zahteve.
-        unauthorized_client: Odjemalec nima pooblastila za izvajanje te zahteve po tej metodi.
-        unsupported_grant_type: Strežnik pooblastil ne podpira vrste odobritve pooblastila.
-        unsupported_response_type: Strežnik pooblastil ne podpira te vrste odziva.
+        server_error: Odobritveni strežnik je naletel na nepričakovano stanje, ki je preprečilo, da bi izpolnil zahtevo.
+        temporarily_unavailable: Odobritveni strežnik zaradi začasne preobremenitve ali vzdrževanja trenutno ne more obdelati zahteve.
+        unauthorized_client: Odjemalec nima odobritve za izvajanje te zahteve po tej metodi.
+        unsupported_grant_type: Odobritveni strežnik ne podpira zahtevane vrste odobritve.
+        unsupported_response_type: Odobritveni strežnik pooblastil ne podpira te vrste odziva.
     flash:
       applications:
         create:
@@ -145,7 +145,7 @@ sl:
           applications: Programi
           oauth2_provider: Ponudnik OAuth2
       application:
-        title: Potrebna je pooblastitev OAuth
+        title: Potrebna je odobritev OAuth
     scopes:
       admin:read: preberi vse podatke na strežniku
       admin:read:accounts: preberi občutljive informacije vseh računov
diff --git a/config/locales/my.yml b/config/locales/my.yml
index 8e01e82afe60e7..d8e83543c691b7 100644
--- a/config/locales/my.yml
+++ b/config/locales/my.yml
@@ -523,6 +523,7 @@ my:
       total_reported: "၎င်းတို့နှင့်ဆိုင်သော အစီရင်ခံစာများ"
       total_storage: မီဒီယာ ပူးတွဲချက်များ
       totals_time_period_hint_html: အောက်တွင်ဖော်ပြထားသော စုစုပေါင်းမှာ အချိန်တိုင်းအတွက် အချက်အလက်များဖြစ်သည်။
+      unknown_instance: လောလောဆယ် ဤဆာဗာတွင် ဤဒိုမိန်း၏ မှတ်တမ်းမရှိပါ။
     invites:
       deactivate_all: အားလုံးပယ်ဖျက်ရန်
       filter:
@@ -1006,6 +1007,13 @@ my:
       hint_html: နောက်ထပ်တစ်ခုသာ။ သင်သည် လူသားဖြစ်ကြောင်း ကျွန်ုပ်တို့ အတည်ပြုရန် လိုအပ်ပါသည် (စပမ်းများကို ရှောင်ရှားနိုင်စေရန် အတွက်ဖြစ်ပါသည်။) အောက်ပါ CAPTCHA ကိုဖြေရှင်းပြီး "Continue" ကို နှိပ်ပါ။
       title: လုံခြုံရေးစစ်ဆေးမှု
     confirmations:
+      awaiting_review: သင့်အီးမေးလ်လိပ်စာကို အတည်ပြုပြီးပါပြီ။ %{domain} စီမံသူများမှ ယခု သင်စာရင်းသွင်းခြင်းကို ပြန်လည်သုံးသပ်နေပါသည်။ သင့်အကောင့်ကို အတည်ပြုပါက အီးမေးလ်တစ်စောင် လက်ခံရရှိမည်ဖြစ်သည်။
+      awaiting_review_title: သင် စာရင်သွင်းထားခြင်းကို စစ်ဆေးနေပါသည်
+      clicking_this_link: ဤလင့်ခ်ကို နှိပ်ပါ
+      login_link: အကောင့်ဝင်ရန်
+      proceed_to_login_html: သင် ယခု %{login_link} သို့ ဆက်သွားနိုင်ပါပြီ။
+      registration_complete: "%{domain} တွင် သင် စာရင်းသွင်းခြင်းမှာ မှန်ကန်ပါပြီ။"
+      welcome_title: ကြိုဆိုပါတယ် %{name}။
       wrong_email_hint: ထိုအီးမေးလ်လိပ်စာ မမှန်ပါက အကောင့်သတ်မှတ်ချက်များတွင် ပြောင်းလဲနိုင်သည်။
     delete_account: အကောင့်ဖျက်ပါ
     delete_account_html: သင့်အကောင့်ဖျက်လိုပါက<a href="%{path}">ဤနေရာတွင် ဆက်လက်လုပ်ဆောင်နိုင်သည်</a>။ အတည်ပြုချက်တောင်းပါမည်။
@@ -1067,6 +1075,7 @@ my:
       functional: သင့်အကောင့်မှာ အပြည့်အဝလုပ်ဆောင်နေပါပြီ။
       pending: သင့်အက်ပလီကေးရှင်းကို ကျွန်ုပ်တို့၏ဝန်ထမ်းများမှ ပြန်လည်သုံးသပ်နေပါသည်။ အချိန်အနည်းငယ်ကြာနိုင်ပါသည်။ သင့်အက်ပလီကေးရှင်းကို အတည်ပြုပြီးပါက အီးမေးလ်တစ်စောင် သင် လက်ခံရရှိမည်ဖြစ်သည်။
       redirecting_to: သင့်အကောင့်မှာ လက်ရှိတွင် %{acct} သို့ ပြန်ညွှန်းနေသောကြောင့် သုံးစွဲ၍မရပါ။
+      self_destruct: "%{domain} ပိတ်သွားသောကြောင့် သင့်အကောင့်သို့ အကန့်အသတ်ဖြင့်သာ ဝင်ရောက်နိုင်မည်ဖြစ်သည်။"
       view_strikes: သင့်အကောင့်ကို ဆန့်ကျင်သည့် ယခင်ကလုပ်ဆောင်ချက်များကို ကြည့်ပါ
     too_fast: ဖောင်တင်သည်မှာ မြန်နေပါသည်။ ထပ်စမ်းကြည့်ပါ။
     use_security_key: လုံခြုံရေးကီးကို သုံးပါ
@@ -1525,6 +1534,8 @@ my:
     over_daily_limit: ယနေ့အတွက် စီစဉ်ထားသည့် ပို့စ်များ၏ ကန့်သတ်ချက် %{limit} ကို ကျော်လွန်သွားပါပြီ
     over_total_limit: စီစဉ်ထားသည့် ပို့စ်များ၏ ကန့်သတ်ချက် %{limit} ကို ကျော်လွန်သွားပါပြီ
     too_soon: စီစဉ်ထားသောရက်စွဲမှာ အနာဂတ်အတွက်ဖြစ်သည်
+  self_destruct:
+    title: ဤဆာဗာ ပိတ်ထားပါသည်
   sessions:
     activity: နောက်ဆုံးလုပ်ဆောင်ချက်
     browser: ဘရောက်ဇာ
diff --git a/config/locales/simple_form.sq.yml b/config/locales/simple_form.sq.yml
index 3256e7378dd915..dc07478070cc2a 100644
--- a/config/locales/simple_form.sq.yml
+++ b/config/locales/simple_form.sq.yml
@@ -256,8 +256,8 @@ sq:
         site_contact_username: Emër përdoruesi kontakti
         site_extended_description: Përshkrim i zgjeruar
         site_short_description: Përshkrim shërbyesi
-        site_terms: Rregulla Privatësie
-        site_title: Emër shërbyesi
+        site_terms: Politika e privatësisë
+        site_title: Emri i serverit
         status_page_url: URL faqeje gjendjesh
         theme: Temë parazgjedhje
         thumbnail: Miniaturë shërbyesi
diff --git a/config/locales/sk.yml b/config/locales/sk.yml
index f16803fb29aa64..b3bc8c2dcd0003 100644
--- a/config/locales/sk.yml
+++ b/config/locales/sk.yml
@@ -585,6 +585,7 @@ sk:
       title: Serverové pravidlá
     settings:
       about:
+        manage_rules: Spravuj serverové pravidlá
         title: Ohľadom
       appearance:
         title: Vzhľad
@@ -607,9 +608,16 @@ sk:
           approved: Pre registráciu je nutné povolenie
           none: Nikto sa nemôže registrovať
           open: Ktokoľvek sa môže zaregistrovať
+      title: Nastavenia servera
     site_uploads:
       delete: Vymaž nahratý súbor
       destroyed_msg: Nahratie bolo zo stránky úspešne vymazané!
+    software_updates:
+      documentation_link: Zisti viac
+      title: Dostupné aktualizácie
+      types:
+        major: Hlavné vydanie
+      version: Verzia
     statuses:
       account: Autor
       application: Aplikácia
diff --git a/config/locales/uk.yml b/config/locales/uk.yml
index 8069c76c6d95c4..85db04715b5727 100644
--- a/config/locales/uk.yml
+++ b/config/locales/uk.yml
@@ -1077,12 +1077,12 @@ uk:
       hint_html: Ще одне! Ми повинні пересвідчитись, що ви людина (щоб ми могли уникнути спаму!). Розв'яжіть CAPTCHA внизу і натисніть кнопку "Продовжити".
       title: Перевірка безпеки
     confirmations:
-      awaiting_review: Ваша електронна адреса підтверджена! Співробітники %{domain} тепер переглядають вашу реєстрацію. Ви отримаєте електронного листа, якщо вони затвердять ваш обліковий запис!
+      awaiting_review: Ваша електронна адреса підтверджена! Наразі співробітники %{domain} розглядають вашу реєстрацію. Ви отримаєте електронний лист, якщо вони затвердять ваш обліковий запис!
       awaiting_review_title: Ваша реєстрація розглядається
       clicking_this_link: натисніть це посилання
       login_link: увійти
       proceed_to_login_html: Тепер ви можете перейти до %{login_link}.
-      redirect_to_app_html: Ви мали бути перенаправлені до програми <strong>%{app_name}</strong>. Якщо цього не сталося, спробуйте %{clicking_this_link} або вручну поверніться до програми.
+      redirect_to_app_html: Вас мало переспрямувати до програми <strong>%{app_name}</strong>. Якщо цього не сталося, спробуйте %{clicking_this_link} або вручну поверніться до програми.
       registration_complete: Ваша реєстрація на %{domain} завершена!
       welcome_title: Ласкаво просимо, %{name}!
       wrong_email_hint: Якщо ця адреса електронної пошти неправильна, можна змінити її в налаштуваннях облікового запису.
diff --git a/config/webpack/rules/index.js b/config/webpack/rules/index.js
index b026857887efbd..4be59f1b6423d5 100644
--- a/config/webpack/rules/index.js
+++ b/config/webpack/rules/index.js
@@ -2,7 +2,6 @@ const babel = require('./babel');
 const css = require('./css');
 const file = require('./file');
 const materialIcons = require('./material_icons');
-const nodeModules = require('./node_modules');
 const tesseract = require('./tesseract');
 
 // Webpack loaders are processed in reverse order
@@ -13,6 +12,5 @@ module.exports = {
   file,
   tesseract,
   css,
-  nodeModules,
   babel,
 };
diff --git a/config/webpack/rules/node_modules.js b/config/webpack/rules/node_modules.js
deleted file mode 100644
index 89c9d422d3ee2a..00000000000000
--- a/config/webpack/rules/node_modules.js
+++ /dev/null
@@ -1,27 +0,0 @@
-const { join } = require('path');
-
-const { settings, env } = require('../configuration');
-
-module.exports = {
-  test: /\.(js|mjs)$/,
-  include: /node_modules/,
-  exclude: [
-    /@babel(?:\/|\\{1,2})runtime/,
-    /tesseract.js/,
-  ],
-  use: [
-    {
-      loader: 'babel-loader',
-      options: {
-        babelrc: false,
-        plugins: [
-          'transform-react-remove-prop-types',
-        ],
-        cacheDirectory: join(settings.cache_path, 'babel-loader-node-modules'),
-        cacheCompression: env.NODE_ENV === 'production',
-        compact: false,
-        sourceMaps: false,
-      },
-    },
-  ],
-};
diff --git a/config/webpack/tests.js b/config/webpack/tests.js
deleted file mode 100644
index e6a8f1c2a95f12..00000000000000
--- a/config/webpack/tests.js
+++ /dev/null
@@ -1,9 +0,0 @@
-// Note: You must restart bin/webpack-dev-server for changes to take effect
-
-const { merge } = require('webpack-merge');
-
-const sharedConfig = require('./shared');
-
-module.exports = merge(sharedConfig, {
-  mode: 'production',
-});
diff --git a/package.json b/package.json
index 40578504e822bb..c5ad74c61cb10a 100644
--- a/package.json
+++ b/package.json
@@ -49,7 +49,6 @@
     "@reduxjs/toolkit": "^1.9.5",
     "@renchap/compression-webpack-plugin": "^6.1.4",
     "@svgr/webpack": "^5.5.0",
-    "abortcontroller-polyfill": "^1.7.5",
     "atrament": "0.2.4",
     "arrow-key-navigation": "^1.2.0",
     "async-mutex": "^0.4.0",
diff --git a/spec/lib/activitypub/activity/create_spec.rb b/spec/lib/activitypub/activity/create_spec.rb
index d7c4c131a20500..5e92cb1d397e23 100644
--- a/spec/lib/activitypub/activity/create_spec.rb
+++ b/spec/lib/activitypub/activity/create_spec.rb
@@ -23,6 +23,109 @@
     stub_request(:get, 'http://example.com/emojib.png').to_return(body: attachment_fixture('emojo.png'), headers: { 'Content-Type' => 'application/octet-stream' })
   end
 
+  describe 'processing posts received out of order' do
+    let(:follower) { Fabricate(:account, username: 'bob') }
+
+    let(:object_json) do
+      {
+        id: [ActivityPub::TagManager.instance.uri_for(sender), 'post1'].join('/'),
+        type: 'Note',
+        to: [
+          'https://www.w3.org/ns/activitystreams#Public',
+          ActivityPub::TagManager.instance.uri_for(follower),
+        ],
+        content: '@bob lorem ipsum',
+        published: 1.hour.ago.utc.iso8601,
+        updated: 1.hour.ago.utc.iso8601,
+        tag: {
+          type: 'Mention',
+          href: ActivityPub::TagManager.instance.uri_for(follower),
+        },
+      }
+    end
+
+    let(:reply_json) do
+      {
+        id: [ActivityPub::TagManager.instance.uri_for(sender), 'reply'].join('/'),
+        type: 'Note',
+        inReplyTo: object_json[:id],
+        to: [
+          'https://www.w3.org/ns/activitystreams#Public',
+          ActivityPub::TagManager.instance.uri_for(follower),
+        ],
+        content: '@bob lorem ipsum',
+        published: Time.now.utc.iso8601,
+        updated: Time.now.utc.iso8601,
+        tag: {
+          type: 'Mention',
+          href: ActivityPub::TagManager.instance.uri_for(follower),
+        },
+      }
+    end
+
+    def activity_for_object(json)
+      {
+        '@context': 'https://www.w3.org/ns/activitystreams',
+        id: [json[:id], 'activity'].join('/'),
+        type: 'Create',
+        actor: ActivityPub::TagManager.instance.uri_for(sender),
+        object: json,
+      }.with_indifferent_access
+    end
+
+    before do
+      follower.follow!(sender)
+    end
+
+    around do |example|
+      Sidekiq::Testing.fake! do
+        example.run
+        Sidekiq::Worker.clear_all
+      end
+    end
+
+    it 'correctly processes posts and inserts them in timelines', :aggregate_failures do
+      # Simulate a temporary failure preventing from fetching the parent post
+      stub_request(:get, object_json[:id]).to_return(status: 500)
+
+      # When receiving the reply…
+      described_class.new(activity_for_object(reply_json), sender, delivery: true).perform
+
+      # NOTE: Refering explicitly to the workers is a bit awkward
+      DistributionWorker.drain
+      FeedInsertWorker.drain
+
+      # …it creates a status with an unknown parent
+      reply = Status.find_by(uri: reply_json[:id])
+      expect(reply.reply?).to be true
+      expect(reply.in_reply_to_id).to be_nil
+
+      # …and creates a notification
+      expect(LocalNotificationWorker.jobs.size).to eq 1
+
+      # …but does not insert it into timelines
+      expect(redis.zscore(FeedManager.instance.key(:home, follower.id), reply.id)).to be_nil
+
+      # When receiving the parent…
+      described_class.new(activity_for_object(object_json), sender, delivery: true).perform
+
+      Sidekiq::Worker.drain_all
+
+      # …it creates a status and insert it into timelines
+      parent = Status.find_by(uri: object_json[:id])
+      expect(parent.reply?).to be false
+      expect(parent.in_reply_to_id).to be_nil
+      expect(reply.reload.in_reply_to_id).to eq parent.id
+
+      # Check that the both statuses have been inserted into the home feed
+      expect(redis.zscore(FeedManager.instance.key(:home, follower.id), parent.id)).to be_within(0.1).of(parent.id.to_f)
+      expect(redis.zscore(FeedManager.instance.key(:home, follower.id), reply.id)).to be_within(0.1).of(reply.id.to_f)
+
+      # Creates two notifications
+      expect(Notification.count).to eq 2
+    end
+  end
+
   describe '#perform' do
     context 'when fetching' do
       subject { described_class.new(json, sender) }
@@ -31,29 +134,67 @@
         subject.perform
       end
 
-      context 'when object has been edited' do
+      context 'when object publication date is below ISO8601 range' do
         let(:object_json) do
           {
             id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
             type: 'Note',
             content: 'Lorem ipsum',
-            published: '2022-01-22T15:00:00Z',
-            updated: '2022-01-22T16:00:00Z',
+            published: '-0977-11-03T08:31:22Z',
           }
         end
 
-        it 'creates status' do
+        it 'creates status with a valid creation date', :aggregate_failures do
+          status = sender.statuses.first
+
+          expect(status).to_not be_nil
+          expect(status.text).to eq 'Lorem ipsum'
+
+          expect(status.created_at).to be_within(30).of(Time.now.utc)
+        end
+      end
+
+      context 'when object publication date is above ISO8601 range' do
+        let(:object_json) do
+          {
+            id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+            type: 'Note',
+            content: 'Lorem ipsum',
+            published: '10000-11-03T08:31:22Z',
+          }
+        end
+
+        it 'creates status with a valid creation date', :aggregate_failures do
           status = sender.statuses.first
 
           expect(status).to_not be_nil
           expect(status.text).to eq 'Lorem ipsum'
+
+          expect(status.created_at).to be_within(30).of(Time.now.utc)
         end
+      end
 
-        it 'marks status as edited' do
+      context 'when object has been edited' do
+        let(:object_json) do
+          {
+            id: [ActivityPub::TagManager.instance.uri_for(sender), '#bar'].join,
+            type: 'Note',
+            content: 'Lorem ipsum',
+            published: '2022-01-22T15:00:00Z',
+            updated: '2022-01-22T16:00:00Z',
+          }
+        end
+
+        it 'creates status with appropriate creation and edition dates', :aggregate_failures do
           status = sender.statuses.first
 
           expect(status).to_not be_nil
+          expect(status.text).to eq 'Lorem ipsum'
+
+          expect(status.created_at).to eq '2022-01-22T15:00:00Z'.to_datetime
+
           expect(status.edited?).to be true
+          expect(status.edited_at).to eq '2022-01-22T16:00:00Z'.to_datetime
         end
       end
 
diff --git a/spec/system/unlogged_spec.rb b/spec/system/unlogged_spec.rb
new file mode 100644
index 00000000000000..c3ebf51d7fb098
--- /dev/null
+++ b/spec/system/unlogged_spec.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'UnloggedBrowsing' do
+  subject { page }
+
+  before do
+    visit root_path
+  end
+
+  it 'loads the home page' do
+    expect(subject).to have_css('div.app-holder')
+
+    expect(subject).to have_css('div.columns-area__panels__main')
+  end
+end
diff --git a/yarn.lock b/yarn.lock
index 9d1b969fc1a7db..dd31a1cc388b7d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2904,11 +2904,6 @@ abort-controller@^3.0.0:
   dependencies:
     event-target-shim "^5.0.0"
 
-abortcontroller-polyfill@^1.7.5:
-  version "1.7.5"
-  resolved "https://registry.yarnpkg.com/abortcontroller-polyfill/-/abortcontroller-polyfill-1.7.5.tgz#6738495f4e901fbb57b6c0611d0c75f76c485bed"
-  integrity sha512-JMJ5soJWP18htbbxJjG7bG6yuI6pRhgJ0scHHTfkUjf6wjP912xZWvM+A4sJK3gqd9E8fcPbDnOefbA9Th/FIQ==
-
 accepts@~1.3.4, accepts@~1.3.5, accepts@~1.3.8:
   version "1.3.8"
   resolved "https://registry.yarnpkg.com/accepts/-/accepts-1.3.8.tgz#0bf0be125b67014adcb0b0921e62db7bffe16b2e"