diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f1dfcfdb8640af1fae30cbf6e88449455e6c8e9f..8fd695813037c4d6046b9d6bf09d6126120003b2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -42,9 +42,7 @@ include:
 variables:
   _PHPUNIT_CONCURRENT: "1"
 #  _PHPUNIT_EXTRA: "--suppress-deprecations"
-#  OPT_IN_TEST_PREVIOUS_MAJOR: '1'
-  OPT_IN_TEST_NEXT_MINOR: '1'
-  OPT_IN_TEST_NEXT_MAJOR: '1'
+  OPT_IN_TEST_PREVIOUS_MAJOR: '1'
 
 #
 # Linting jobs are passing so any issue that breaks them should fix them.
diff --git a/src/ConfigSelector.php b/src/ConfigSelector.php
index c9962e9b1fb28499d4515ce1fbbb1d2140fc678c..46bcd7ea7d1c208cb455fabed3703de492d8ebf1 100644
--- a/src/ConfigSelector.php
+++ b/src/ConfigSelector.php
@@ -56,7 +56,8 @@ class ConfigSelector {
     #[Autowire(service: 'logger.channel.config_selector')]
     protected LoggerInterface $logger,
     protected StateInterface $state,
-    protected MessengerInterface $messenger) {
+    protected MessengerInterface $messenger,
+  ) {
   }
 
   /**
@@ -288,7 +289,7 @@ class ConfigSelector {
         $url = $entity->toUrl();
       }
     }
-    catch (\Exception $e) {
+    catch (\Exception) {
     }
     return isset($url) ? $url->toString() : '';
   }
diff --git a/src/DecoratingConfigInstaller.php b/src/DecoratingConfigInstaller.php
index 766b56d33cd160aaeab1983ec848ef54551ac59e..5df91b70d0c2b26956f50a3c3d78b9b87d82945b 100644
--- a/src/DecoratingConfigInstaller.php
+++ b/src/DecoratingConfigInstaller.php
@@ -24,7 +24,8 @@ class DecoratingConfigInstaller implements ConfigInstallerInterface {
    */
   public function __construct(
     protected ConfigInstallerInterface $decoratedService,
-    protected ConfigSelector $configSelector) {
+    protected ConfigSelector $configSelector,
+  ) {
   }
 
   /**
@@ -37,7 +38,7 @@ class DecoratingConfigInstaller implements ConfigInstallerInterface {
   /**
    * {@inheritdoc}
    */
-  public function installOptionalConfig(StorageInterface $storage = NULL, $dependency = []): void {
+  public function installOptionalConfig(?StorageInterface $storage = NULL, $dependency = []): void {
     $this->decoratedService->installOptionalConfig($storage, $dependency);
     if ($storage === NULL && empty($dependency)) {
       // This is not called as part of a regular module install. It's called
diff --git a/tests/modules/config_selector_ui_test/config_selector_ui_test.install b/tests/modules/config_selector_ui_test/config_selector_ui_test.install
index a325222c494bbb3de4670864a8c9002f53e6acd1..48822b52015112158fb35266126df54050c223eb 100644
--- a/tests/modules/config_selector_ui_test/config_selector_ui_test.install
+++ b/tests/modules/config_selector_ui_test/config_selector_ui_test.install
@@ -1,5 +1,11 @@
 <?php
 
+/**
+ * @file
+ */
+
+declare(strict_types=1);
+
 /**
  * @file
  * The Configuration Selector UI Test module install methods.
diff --git a/tests/src/Functional/ConfigSelectorProfileTest.php b/tests/src/Functional/ConfigSelectorProfileTest.php
index cc2566516f1ed2c6e7929a721a59847f9c7f5fca..7fdd8a3f0fc2934432a2643abea249dafa65047c 100644
--- a/tests/src/Functional/ConfigSelectorProfileTest.php
+++ b/tests/src/Functional/ConfigSelectorProfileTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\Tests\config_selector\Functional;
 
 use Drupal\Tests\BrowserTestBase;
diff --git a/tests/src/Functional/ConfigSelectorUiTest.php b/tests/src/Functional/ConfigSelectorUiTest.php
index 9633800cfc0b73d0d91b0a00c53945ac07a7e9b7..edf3f73b19ee4375cfd612810dabb52527cbf834 100644
--- a/tests/src/Functional/ConfigSelectorUiTest.php
+++ b/tests/src/Functional/ConfigSelectorUiTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\Tests\config_selector\Functional;
 
 use Drupal\config_selector\Entity\Feature;
diff --git a/tests/src/Kernel/ActiveEntityTest.php b/tests/src/Kernel/ActiveEntityTest.php
index eb35a9166ce1b18646a62b69f2ab3e717a296a63..81cd580f0910ef3b105b823e6235d9b4f79bb5ee 100644
--- a/tests/src/Kernel/ActiveEntityTest.php
+++ b/tests/src/Kernel/ActiveEntityTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\Tests\config_selector\Kernel;
 
 use Drupal\Core\Entity\EntityStorageInterface;
diff --git a/tests/src/Kernel/ConfigSelectorTest.php b/tests/src/Kernel/ConfigSelectorTest.php
index 82c09ecae84cf0be4eb5ae7119b346e2aca8fe38..3a9ff32b4929473c700dc3717ab8662a9f560c2d 100644
--- a/tests/src/Kernel/ConfigSelectorTest.php
+++ b/tests/src/Kernel/ConfigSelectorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\Tests\config_selector\Kernel;
 
 use Drupal\config_selector\TestLogger;
diff --git a/tests/src/Unit/ConfigSelectorTest.php b/tests/src/Unit/ConfigSelectorTest.php
index 5e4ab127cf4a0b2c9730cfdb65790e374555e69c..6d6545363519efd34aeddd6ceb0cb62ae7b0512e 100644
--- a/tests/src/Unit/ConfigSelectorTest.php
+++ b/tests/src/Unit/ConfigSelectorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\Tests\config_selector\Unit;
 
 use Drupal\config_selector\ConfigSelector;