[ci skip] Update README for new major version 2.0.0 changes

Explain new import and link commands introduced in version 2.0.0. Inform users about deprecated files and the need to create backups before updating. Provide links to previous versions supporting older setups.

README.md

@@ -7,9 +7,22 @@ bStat Metrics can be found [here](https://bstats.org/plugin/bukkit/TheNextLvl%20
 ## Versions
 
 > [!IMPORTANT]
-> Worlds only supports the latest version of Paper (1.20.6)<br>
-> The latest version of Worlds requires Java 21
-
+> The latest major version (2.0.0) changed the way how worlds and links are loaded<br/>
+> When updating from any (1.x.x) version you'll have to import your worlds using the command
+> `/world import <world> [<key>] [<dimension>] [<generator>]`<br/>
+> To link your worlds again you have to use `/world link create <source> <destination>`
+
+> [!NOTE]
+> World images (`*.image`) do no longer exist, and you can safely delete all remanence of them<br/>
+> The files `links.json` and `config.json` in `plugins/Worlds` also no longer exist and can be safely removed<br/>
+> If you didn't change anything about the translations or presets, it is recommended to regenerate them by deleting the
+> folders (`Worlds/translations` and `Worlds/presets`)
+>
+> **As with all major updates that introduce breaking changes, make sure to create backups before updating**<br/>
+> If you encounter any issues after updating please report
+> them [to us](https://github.com/TheNextLvl-net/worlds/issues/new/choose)
+
+[Latest version supporting 1.20.6 (Java 21)](https://github.com/TheNextLvl-net/worlds/releases/tag/v1.2.5)<br>
 [Latest version supporting 1.19/1.20.4 (Java 19)](https://github.com/TheNextLvl-net/worlds/releases/tag/v1.1.6)<br>
 [Latest version supporting 1.19/1.20.4 (Java 17)](https://github.com/TheNextLvl-net/worlds/releases/tag/v1.1.3)<br>