diff --git a/.travis.yml b/.travis.yml
index 8ce365be..feddc2d9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -26,6 +26,12 @@ matrix:
     - php: 7.3
       env: COVERAGE=true PHPUNIT_FLAGS="-v --coverage-text"
 
+    - php: 7.4
+      env: COVERAGE=true PHPUNIT_FLAGS="-v --coverage-text"
+
+    - php: 8.0
+      env: COVERAGE=true PHPUNIT_FLAGS="-v --coverage-text"
+
       # Latest commit to master
     - php: 7.3
       env: STABILITY="dev"
diff --git a/Tests/Functional/AbstractFunctionalTestCase.php b/Tests/Functional/AbstractFunctionalTestCase.php
index 58552630..cf98cc11 100644
--- a/Tests/Functional/AbstractFunctionalTestCase.php
+++ b/Tests/Functional/AbstractFunctionalTestCase.php
@@ -32,7 +32,7 @@ abstract class AbstractFunctionalTestCase extends TestCase
 
     abstract protected function getEncryptor(): EncryptorInterface;
 
-    public function setUp()
+    public function setUp(): void
     {
         // Create a simple "default" Doctrine ORM configuration for Annotations
         $isDevMode                 = true;
@@ -73,7 +73,7 @@ public function setUp()
         error_reporting(E_ALL);
     }
 
-    public function tearDown()
+    public function tearDown(): void
     {
         unlink($this->dbFile);
     }
@@ -132,4 +132,4 @@ public function assertStringDoesNotContain($needle, $string, $ignoreCase = false
 
         static::assertThat($string, $constraint, $message);
     }
-}
\ No newline at end of file
+}
diff --git a/Tests/Functional/BasicQueryTest/AbstractBasicQueryTestCase.php b/Tests/Functional/BasicQueryTest/AbstractBasicQueryTestCase.php
index 442b6f66..0065311c 100644
--- a/Tests/Functional/BasicQueryTest/AbstractBasicQueryTestCase.php
+++ b/Tests/Functional/BasicQueryTest/AbstractBasicQueryTestCase.php
@@ -8,7 +8,7 @@
 
 abstract class AbstractBasicQueryTestCase extends AbstractFunctionalTestCase
 {
-    public function testPersistEntity()
+    public function testPersistEntity(): void
     {
         $user = new CascadeTarget();
         $user->setNotSecret('My public information');
@@ -21,7 +21,7 @@ public function testPersistEntity()
         $this->assertEquals(3,$this->getCurrentQueryCount());
     }
 
-    public function testNoUpdateOnReadEncrypted()
+    public function testNoUpdateOnReadEncrypted(): void
     {
         $this->entityManager->beginTransaction();
         $this->assertEquals(1,$this->getCurrentQueryCount());
@@ -57,7 +57,7 @@ public function testNoUpdateOnReadEncrypted()
         $this->assertEquals(4,$this->getCurrentQueryCount());
     }
 
-    public function testStoredDataIsEncrypted()
+    public function testStoredDataIsEncrypted(): void
     {
         $user = new CascadeTarget();
         $user->setNotSecret('My public information');
diff --git a/Tests/Functional/DoctrineEncryptSubscriber/AbstractDoctrineEncryptSubscriberTestCase.php b/Tests/Functional/DoctrineEncryptSubscriber/AbstractDoctrineEncryptSubscriberTestCase.php
index 7b113de6..2c11b33f 100644
--- a/Tests/Functional/DoctrineEncryptSubscriber/AbstractDoctrineEncryptSubscriberTestCase.php
+++ b/Tests/Functional/DoctrineEncryptSubscriber/AbstractDoctrineEncryptSubscriberTestCase.php
@@ -11,7 +11,7 @@
 
 abstract class AbstractDoctrineEncryptSubscriberTestCase extends AbstractFunctionalTestCase
 {
-    public function testEncryptionHappensOnOnlyAnnotatedFields()
+    public function testEncryptionHappensOnOnlyAnnotatedFields(): void
     {
         $secret    = "It's a secret";
         $notSecret = "You're all welcome to know this.";
@@ -44,7 +44,7 @@ public function testEncryptionHappensOnOnlyAnnotatedFields()
         $this->assertEquals($secret, $decrypted);
     }
 
-    public function testEncryptionCascades()
+    public function testEncryptionCascades(): void
     {
         $secret        = "It's a secret";
         $notSecret     = "You're all welcome to know this.";
@@ -87,7 +87,7 @@ public function testEncryptionCascades()
      * @throws \Doctrine\DBAL\DBALException
      * @throws \Doctrine\ORM\OptimisticLockException
      */
-    public function testEncryptionDoesNotHappenWhenThereIsNoChange()
+    public function testEncryptionDoesNotHappenWhenThereIsNoChange(): void
     {
         $secret    = "It's a secret";
         $notSecret = "You're all welcome to know this.";
@@ -155,7 +155,7 @@ public function testEncryptionDoesNotHappenWhenThereIsNoChange()
 
     }
 
-    public function testEncryptionDoesHappenWhenASecretIsChanged()
+    public function testEncryptionDoesHappenWhenASecretIsChanged(): void
     {
         $secret    = "It's a secret";
         $notSecret = "You're all welcome to know this.";
@@ -198,4 +198,4 @@ public function testEncryptionDoesHappenWhenASecretIsChanged()
         $this->assertStringEndsWith('<ENC>', $shouldBeDifferentFromBefore); // is encrypted
         $this->assertNotEquals($originalEncryption, $shouldBeDifferentFromBefore);
     }
-}
\ No newline at end of file
+}
diff --git a/Tests/Unit/DependencyInjection/DoctrineEncryptExtensionTest.php b/Tests/Unit/DependencyInjection/DoctrineEncryptExtensionTest.php
index 42b422c8..4aced3d8 100644
--- a/Tests/Unit/DependencyInjection/DoctrineEncryptExtensionTest.php
+++ b/Tests/Unit/DependencyInjection/DoctrineEncryptExtensionTest.php
@@ -16,12 +16,12 @@ class DoctrineEncryptExtensionTest extends TestCase
      */
     private $extension;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         $this->extension = new DoctrineEncryptExtension();
     }
 
-    public function testConfigLoadHalite()
+    public function testConfigLoadHalite(): void
     {
         $container = $this->createContainer();
         $this->extension->load([[]], $container);
@@ -29,7 +29,7 @@ public function testConfigLoadHalite()
         $this->assertSame(HaliteEncryptor::class, $container->getParameter('ambta_doctrine_encrypt.encryptor_class_name'));
     }
 
-    public function testConfigLoadDefuse()
+    public function testConfigLoadDefuse(): void
     {
         $container = $this->createContainer();
 
@@ -41,7 +41,7 @@ public function testConfigLoadDefuse()
         $this->assertSame(DefuseEncryptor::class, $container->getParameter('ambta_doctrine_encrypt.encryptor_class_name'));
     }
 
-    public function testConfigLoadCustom()
+    public function testConfigLoadCustom(): void
     {
         $container = $this->createContainer();
         $config = [
@@ -54,7 +54,7 @@ public function testConfigLoadCustom()
         $this->assertSame(self::class, $container->getParameter('ambta_doctrine_encrypt.encryptor_class_name'));
     }
 
-    private function createContainer()
+    private function createContainer(): ContainerBuilder
     {
         $container = new ContainerBuilder(
             new ParameterBag(['kernel.debug' => false])
diff --git a/Tests/Unit/Encryptors/DefuseEncryptorTest.php b/Tests/Unit/Encryptors/DefuseEncryptorTest.php
index c57e9813..cf3e0d8e 100644
--- a/Tests/Unit/Encryptors/DefuseEncryptorTest.php
+++ b/Tests/Unit/Encryptors/DefuseEncryptorTest.php
@@ -9,7 +9,7 @@ class DefuseEncryptorTest extends TestCase
 {
     private const DATA = 'foobar';
 
-    public function testEncrypt()
+    public function testEncrypt(): void
     {
         $keyfile = __DIR__.'/fixtures/defuse.key';
         $key = file_get_contents($keyfile);
@@ -24,7 +24,7 @@ public function testEncrypt()
         $this->assertSame($key, $newkey, 'The key must not be modified');
     }
 
-    public function testGenerateKey()
+    public function testGenerateKey(): void
     {
         $keyfile = sys_get_temp_dir().'/defuse-'.md5(time());
         if (file_exists($keyfile)) {
diff --git a/Tests/Unit/Encryptors/HaliteEncryptorTest.php b/Tests/Unit/Encryptors/HaliteEncryptorTest.php
index 96c064b5..794b5a2f 100644
--- a/Tests/Unit/Encryptors/HaliteEncryptorTest.php
+++ b/Tests/Unit/Encryptors/HaliteEncryptorTest.php
@@ -9,7 +9,7 @@ class HaliteEncryptorTest extends TestCase
 {
     private const DATA = 'foobar';
 
-    public function testEncryptExtension()
+    public function testEncryptExtension(): void
     {
         if (! extension_loaded('sodium')) {
             $this->markTestSkipped('This test only runs when the sodium extension is enabled.');
@@ -27,7 +27,7 @@ public function testEncryptExtension()
         $this->assertSame($key, $newkey, 'The key must not be modified');
     }
 
-    public function testGenerateKey()
+    public function testGenerateKey(): void
     {
         if (! extension_loaded('sodium')) {
             $this->markTestSkipped('This test only runs when the sodium extension is enabled.');
@@ -46,7 +46,7 @@ public function testGenerateKey()
     }
 
 
-    public function testEncryptWithoutExtensionThrowsException()
+    public function testEncryptWithoutExtensionThrowsException(): void
     {
         if (extension_loaded('sodium')) {
             $this->markTestSkipped('This only runs when the sodium extension is disabled.');
diff --git a/Tests/Unit/Subscribers/DoctrineEncryptSubscriberTest.php b/Tests/Unit/Subscribers/DoctrineEncryptSubscriberTest.php
index 59b880cb..0a407cc3 100644
--- a/Tests/Unit/Subscribers/DoctrineEncryptSubscriberTest.php
+++ b/Tests/Unit/Subscribers/DoctrineEncryptSubscriberTest.php
@@ -35,7 +35,7 @@ class DoctrineEncryptSubscriberTest extends TestCase
      */
     private $reader;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         $this->encryptor = $this->createMock(EncryptorInterface::class);
         $this->encryptor
@@ -71,7 +71,7 @@ protected function setUp()
         $this->subscriber = new DoctrineEncryptSubscriber($this->reader, $this->encryptor);
     }
 
-    public function testSetRestorEncryptor()
+    public function testSetRestorEncryptor(): void
     {
         $replaceEncryptor = $this->createMock(EncryptorInterface::class);
 
@@ -82,7 +82,7 @@ public function testSetRestorEncryptor()
         $this->assertSame($this->encryptor, $this->subscriber->getEncryptor());
     }
 
-    public function testProcessFieldsEncrypt()
+    public function testProcessFieldsEncrypt(): void
     {
         $user = new User('David', 'Switzerland');
 
@@ -92,7 +92,7 @@ public function testProcessFieldsEncrypt()
         $this->assertStringStartsWith('encrypted-', $user->getAddress());
     }
 
-    public function testProcessFieldsEncryptExtend()
+    public function testProcessFieldsEncryptExtend(): void
     {
         $user = new ExtendedUser('David', 'Switzerland', 'extra');
 
@@ -103,7 +103,7 @@ public function testProcessFieldsEncryptExtend()
         $this->assertStringStartsWith('encrypted-', $user->extra);
     }
 
-    public function testProcessFieldsEncryptEmbedded()
+    public function testProcessFieldsEncryptEmbedded(): void
     {
         $withUser = new WithUser('Thing', 'foo', new User('David', 'Switzerland'));
 
@@ -115,7 +115,7 @@ public function testProcessFieldsEncryptEmbedded()
         $this->assertStringStartsWith('encrypted-', $withUser->user->getAddress());
     }
 
-    public function testProcessFieldsEncryptNull()
+    public function testProcessFieldsEncryptNull(): void
     {
         $user = new User('David', null);
 
@@ -125,7 +125,7 @@ public function testProcessFieldsEncryptNull()
         $this->assertNull($user->getAddress());
     }
 
-    public function testProcessFieldsNoEncryptor()
+    public function testProcessFieldsNoEncryptor(): void
     {
         $user = new User('David', 'Switzerland');
 
@@ -136,7 +136,7 @@ public function testProcessFieldsNoEncryptor()
         $this->assertSame('Switzerland', $user->getAddress());
     }
 
-    public function testProcessFieldsDecrypt()
+    public function testProcessFieldsDecrypt(): void
     {
         $user = new User('encrypted-David<ENC>', 'encrypted-Switzerland<ENC>');
 
@@ -146,7 +146,7 @@ public function testProcessFieldsDecrypt()
         $this->assertSame('Switzerland', $user->getAddress());
     }
 
-    public function testProcessFieldsDecryptExtended()
+    public function testProcessFieldsDecryptExtended(): void
     {
         $user = new ExtendedUser('encrypted-David<ENC>', 'encrypted-Switzerland<ENC>', 'encrypted-extra<ENC>');
 
@@ -157,7 +157,7 @@ public function testProcessFieldsDecryptExtended()
         $this->assertSame('extra', $user->extra);
     }
 
-    public function testProcessFieldsDecryptEmbedded()
+    public function testProcessFieldsDecryptEmbedded(): void
     {
         $withUser = new WithUser('encrypted-Thing<ENC>', 'foo', new User('encrypted-David<ENC>', 'encrypted-Switzerland<ENC>'));
 
@@ -169,7 +169,7 @@ public function testProcessFieldsDecryptEmbedded()
         $this->assertSame('Switzerland', $withUser->user->getAddress());
     }
 
-    public function testProcessFieldsDecryptNull()
+    public function testProcessFieldsDecryptNull(): void
     {
         $user = new User('encrypted-David<ENC>', null);
 
@@ -179,7 +179,7 @@ public function testProcessFieldsDecryptNull()
         $this->assertNull($user->getAddress());
     }
 
-    public function testProcessFieldsDecryptNonEncrypted()
+    public function testProcessFieldsDecryptNonEncrypted(): void
     {
         // no trailing <ENC> but somethint that our mock decrypt would change if called
         $user = new User('encrypted-David', 'encrypted-Switzerland');
@@ -193,7 +193,7 @@ public function testProcessFieldsDecryptNonEncrypted()
     /**
      * Test that fields are encrypted before flushing.
      */
-    public function testOnFlush()
+    public function testOnFlush(): void
     {
         $user = new User('David', 'Switzerland');
 
@@ -222,7 +222,7 @@ public function testOnFlush()
     /**
      * Test that fields are decrypted again after flushing
      */
-    public function testPostFlush()
+    public function testPostFlush(): void
     {
         $user = new User('encrypted-David<ENC>', 'encrypted-Switzerland<ENC>');
 
diff --git a/composer.json b/composer.json
index c463c326..233846ae 100644
--- a/composer.json
+++ b/composer.json
@@ -5,7 +5,7 @@
   "license": "MIT",
   "description": "Encrypted symfony entity's by verified and standardized libraries",
   "require": {
-    "php": "^7.2",
+    "php": "^7.2|^8.0",
     "paragonie/halite": "^4.6",
     "paragonie/sodium_compat": "^1.5",
     "doctrine/orm": "^2.5",
@@ -16,7 +16,7 @@
     "symfony/config": "^4.1|^5.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^6.5",
+    "phpunit/phpunit": "^8.0|^9.0",
     "defuse/php-encryption": "^2.1"
   },
   "suggest": {
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 3d09a6ff..80037be4 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -4,8 +4,7 @@
          colors="true"
          convertErrorsToExceptions="true"
          convertNoticesToExceptions="true"
-         convertWarningsToExceptions="true"
-         syntaxCheck="true">
+         convertWarningsToExceptions="true">
 
     <testsuites>
         <testsuite name="unit">
@@ -16,15 +15,15 @@
         </testsuite>
     </testsuites>
 
-    <filter>
-        <whitelist>
+    <coverage>
+        <include>
             <directory>./Command</directory>
             <directory>./Configuration</directory>
             <directory>./DependencyInjection</directory>
             <directory>./Encryptors</directory>
             <directory>./Subscribers</directory>
-        </whitelist>
-    </filter>
+        </include>
+    </coverage>
 
     <php>
         <env name="KERNEL_DIR" value="./Tests/Functional/Fixtures/app" />