diff --git a/UPGRADE.md b/UPGRADE.md
index 1bc3828..d8261c8 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -1,6 +1,11 @@
 UPGRADE to 4.0
 ==============
 
+## Type declarations
+
+Type declarations have been added everywhere. Types extending or implementing
+types from this bundle need to be updated to match the new signatures.
+
 ## Final classes
 
 Some classes have been marked as `final` because they are not supposed to be
@@ -39,7 +44,7 @@ services:
     and so no longer have a ``$this->container`` property. You *can* manually
     implement this interface. Or, a better idea is to update your fixtures
     to use dependency injection:
-    
+
 ```diff
 class MyFixture extends Fixture
 {
@@ -61,7 +66,7 @@ class MyFixture extends Fixture
 * The base ``Fixture`` class no longer implements ``DependentFixtureInterface``.
     If you want to have a ``getDependencies()`` method, be sure to implement
     this interface explicitly:
-    
+
 ```diff
 + use Doctrine\Common\DataFixtures\DependentFixtureInterface;
 
diff --git a/composer.json b/composer.json
index 10ff88c..35831ab 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
         "doctrine/doctrine-bundle": "^2.2",
         "doctrine/orm": "^2.14.0 || ^3.0",
         "doctrine/persistence": "^2.4 || ^3.0",
-        "psr/log": "^1 || ^2 || ^3",
+        "psr/log": "^2 || ^3",
         "symfony/config": "^5.4 || ^6.0 || ^7.0",
         "symfony/console": "^5.4 || ^6.0 || ^7.0",
         "symfony/dependency-injection": "^5.4 || ^6.0 || ^7.0",
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
deleted file mode 100644
index cfdaaf3..0000000
--- a/phpstan-baseline.neon
+++ /dev/null
@@ -1,25 +0,0 @@
-parameters:
-	ignoreErrors:
-		-
-			message: '#^Method Psr\\Log\\AbstractLogger@anonymous/src/Command/LoadDataFixturesDoctrineCommand\.php\:120\:\:log\(\) has parameter \$message with no type specified\.$#'
-			identifier: missingType.parameter
-			count: 1
-			path: src/Command/LoadDataFixturesDoctrineCommand.php
-
-		-
-			message: '#^Method Doctrine\\Bundle\\FixturesBundle\\Loader\\SymfonyFixturesLoader\:\:createFixture\(\) has parameter \$class with no type specified\.$#'
-			identifier: missingType.parameter
-			count: 1
-			path: src/Loader/SymfonyFixturesLoader.php
-
-		-
-			message: '#^Constructor of class Doctrine\\Bundle\\FixturesBundle\\Tests\\Fixtures\\FooBundle\\DataFixtures\\RequiredConstructorArgsFixtures has an unused parameter \$fooRequiredArg\.$#'
-			identifier: constructor.unusedParameter
-			count: 1
-			path: tests/Fixtures/FooBundle/DataFixtures/RequiredConstructorArgsFixtures.php
-
-		-
-			message: '#^Method Doctrine\\Bundle\\FixturesBundle\\Tests\\IntegrationTestKernel\:\:registerBundles\(\) return type has no value type specified in iterable type array\.$#'
-			identifier: missingType.iterableValue
-			count: 1
-			path: tests/IntegrationTestKernel.php
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 45296fa..004e030 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -4,9 +4,3 @@ parameters:
     paths:
         - src
         - tests
-    excludePaths:
-        # Contains an issue that cannot be ignored
-        - tests/IntegrationTest.php
-
-includes:
-    - phpstan-baseline.neon
diff --git a/src/Command/LoadDataFixturesDoctrineCommand.php b/src/Command/LoadDataFixturesDoctrineCommand.php
index de63e8b..b5e876e 100644
--- a/src/Command/LoadDataFixturesDoctrineCommand.php
+++ b/src/Command/LoadDataFixturesDoctrineCommand.php
@@ -13,6 +13,7 @@
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\Persistence\ManagerRegistry;
 use Psr\Log\AbstractLogger;
+use Stringable;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
@@ -123,7 +124,7 @@ public function __construct(private SymfonyStyle $ui)
             }
 
             /** {@inheritDoc} */
-            public function log($level, $message, array $context = []): void
+            public function log(mixed $level, string|Stringable $message, array $context = []): void
             {
                 $this->ui->text(sprintf('  <comment>></comment> <info>%s</info>', $message));
             }
diff --git a/src/Loader/SymfonyFixturesLoader.php b/src/Loader/SymfonyFixturesLoader.php
index 5558b82..faa7b09 100644
--- a/src/Loader/SymfonyFixturesLoader.php
+++ b/src/Loader/SymfonyFixturesLoader.php
@@ -66,7 +66,7 @@ public function addFixture(FixtureInterface $fixture): void
      * Overridden to not allow new fixture classes to be instantiated.
      * {@inheritDoc}
      */
-    protected function createFixture($class): FixtureInterface
+    protected function createFixture(string $class): FixtureInterface
     {
         /*
          * We don't actually need to create the fixture. We just
diff --git a/tests/Fixtures/FooBundle/DataFixtures/RequiredConstructorArgsFixtures.php b/tests/Fixtures/FooBundle/DataFixtures/RequiredConstructorArgsFixtures.php
index cf4d316..35a0b3f 100644
--- a/tests/Fixtures/FooBundle/DataFixtures/RequiredConstructorArgsFixtures.php
+++ b/tests/Fixtures/FooBundle/DataFixtures/RequiredConstructorArgsFixtures.php
@@ -9,7 +9,7 @@
 
 class RequiredConstructorArgsFixtures implements ORMFixtureInterface
 {
-    public function __construct(string $fooRequiredArg)
+    public function __construct(public string $fooRequiredArg)
     {
     }
 
diff --git a/tests/IntegrationTestKernel.php b/tests/IntegrationTestKernel.php
index 524a846..15ce41b 100644
--- a/tests/IntegrationTestKernel.php
+++ b/tests/IntegrationTestKernel.php
@@ -11,6 +11,7 @@
 use Symfony\Component\Config\Loader\LoaderInterface;
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\HttpKernel\Bundle\BundleInterface;
 use Symfony\Component\HttpKernel\Kernel;
 
 use function rand;
@@ -35,6 +36,8 @@ protected function getContainerClass(): string
 
     /**
      * {@inheritDoc}
+     *
+     * @return array<mixed, BundleInterface>
      */
     public function registerBundles(): array
     {