diff --git a/.circleci/config.yml b/.circleci/config.yml
deleted file mode 100644
index c35a017..0000000
--- a/.circleci/config.yml
+++ /dev/null
@@ -1,49 +0,0 @@
-version: 2.1
-
-executors:
-  php83:
-    docker:
-      - image: skpr/php-cli:8.3-v2-latest
-
-workflows:
-  build:
-    jobs:
-      - build:
-          matrix:
-            parameters:
-              php: ["php83"]
-              composer-opts: ["", "--prefer-lowest"]
-
-jobs:
-  build:
-    parameters:
-      php:
-        type: executor
-      composer-opts:
-        type: string
-    executor: << parameters.php >>
-    working_directory: /data
-    steps:
-      - checkout
-      - restore_cache:
-          keys:
-            - deps-{{ arch }}
-      - run:
-          name: "Install Dependencies"
-          command: composer update --prefer-dist --no-progress --no-interaction << parameters.composer-opts >>
-      - save_cache:
-          key: deps-{{ arch }}
-          paths:
-            - vendor
-      - run:
-          name: "Lint"
-          command: ./bin/phpcs --runtime-set testVersion 8.0-
-      - run:
-          name: "Test"
-          command: |
-            mkdir -p ~/phpunit
-            ./bin/phpunit --log-junit ~/phpunit/phpunit.xml
-      - store_test_results:
-          path: ~/phpunit
-      - store_artifacts:
-          path: ~/phpunit
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
new file mode 100644
index 0000000..3345fec
--- /dev/null
+++ b/.github/workflows/build.yml
@@ -0,0 +1,45 @@
+name: 🏗 Build
+
+on:
+  pull_request:
+    types: [ synchronize, opened, reopened, ready_for_review ]
+  push:
+    branches: [ main ]
+
+permissions:
+  checks: write
+  pull-requests: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        prefer_lowest: ["", "--prefer-lowest"]
+    container:
+      image: skpr/php-cli:8.4-dev-v2-latest
+      options:
+        --pull always
+        --user 1001:1001
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          show-progress: false
+      - name: 📦 Composer Update
+        run: composer update --with-all-dependencies --prefer-dist --no-progress --no-interaction ${{ matrix.prefer_lowest }}
+      - name: 🧹 PHPCS
+        run: ./bin/phpcs --report=checkstyle -q | ./bin/cs2pr
+      - name: 🧹 PHPStan
+        run: ./bin/phpstan --error-format=github analyse -v
+      - name: ➕ Add matcher
+        run: |
+          cat << 'EOF' > .github/phpunit-failure.json
+          {"problemMatcher":[{"owner":"phpunit-failure","severity":"error","pattern":[{"regexp":"##teamcity\\[testFailed[^\\]]*message='([^']*)'[^\\]]*details='/data/([^:]+):(\\d+)","message":1,"file":2,"line":3}]}]}
+          EOF
+          echo "::add-matcher::.github/phpunit-failure.json"
+      - name: ⚡ Run Tests
+        run: ./bin/phpunit --teamcity
+      - name: ➖ Remove matcher
+        if: always()
+        run: echo "::remove-matcher owner=phpunit-failure::"
diff --git a/composer.json b/composer.json
index 73ec539..e14634f 100644
--- a/composer.json
+++ b/composer.json
@@ -15,13 +15,16 @@
   ],
   "require": {
     "php": "^8.1",
-    "phpunit/phpunit": "^10.5",
-    "symfony/console": "^6.4||^7"
+    "phpunit/phpunit": "^10.5||^11.5",
+    "symfony/console": "^6.4||^7.4"
   },
   "require-dev": {
-    "dealerdirect/phpcodesniffer-composer-installer": "^0.7.1",
-    "drupal/coder": "~8.3.12",
-    "phpcompatibility/php-compatibility": "^9.3"
+    "dealerdirect/phpcodesniffer-composer-installer": "^1.2",
+    "drupal/coder": "~8.3.31",
+    "phpcompatibility/php-compatibility": "^9.3",
+    "phpstan/phpstan": "^2.1",
+    "phpstan/phpstan-deprecation-rules": "^2.0",
+    "staabm/annotate-pull-request-from-checkstyle": "^1.8"
   },
   "autoload": {
     "psr-4": {"PhpUnitFinder\\": "src/"}
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..0524186
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,6 @@
+parameters:
+	paths:
+		- src
+		- tests
+	level: 6
+	reportUnmatchedIgnoredErrors: false
diff --git a/phpunit.xml b/phpunit.xml
index 86e75cb..304454b 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,10 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!-- TODO set checkForUnintentionallyCoveredCode="true" once https://www.drupal.org/node/2626832 is resolved. -->
-<!-- PHPUnit expects functional tests to be run with either a privileged user
- or your current system user. See core/tests/README.md and
- https://www.drupal.org/node/2116263 for details.
--->
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="tests/bootstrap.php" colors="true" beStrictAboutTestsThatDoNotTestAnything="true" beStrictAboutOutputDuringTests="true" beStrictAboutChangesToGlobalState="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.5/phpunit.xsd">
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="tests/bootstrap.php" colors="true" beStrictAboutTestsThatDoNotTestAnything="true" beStrictAboutOutputDuringTests="true" beStrictAboutChangesToGlobalState="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/11.5/phpunit.xsd">
   <php>
     <!-- Set error reporting to E_ALL. -->
     <ini name="error_reporting" value="32767"/>
diff --git a/tests/Unit/FinderTest.php b/tests/Unit/FinderTest.php
index 2a32874..f134711 100644
--- a/tests/Unit/FinderTest.php
+++ b/tests/Unit/FinderTest.php
@@ -14,20 +14,14 @@ class FinderTest extends TestCase {
   /**
    * A stub test.
    */
-  public function testDiscovery() {
+  public function testDiscovery(): void {
     $command = new CommandTester(new FinderCommand());
     $command->execute([
       '--config-file' => dirname(__DIR__) . '/fixtures/phpunit.xml'
     ]);
     $output = $command->getDisplay();
-    $this->assertNotNull($output);
-    if (method_exists($this, 'assertStringContainsString')) {
-      $this->assertStringContainsString('TestUnitTest.php', $output);
-      $this->assertStringContainsString('TestFunctionalTest.php', $output);
-      return;
-    }
-    $this->assertContains('TestUnitTest.php', $output);
-    $this->assertContains('TestFunctionalTest.php', $output);
+    $this->assertStringContainsString('TestUnitTest.php', $output);
+    $this->assertStringContainsString('TestFunctionalTest.php', $output);
   }
 
 }
diff --git a/tests/fixtures/tests/Functional/TestFunctionalTest.php b/tests/fixtures/tests/Functional/TestFunctionalTest.php
index 3ee4ed8..3765978 100644
--- a/tests/fixtures/tests/Functional/TestFunctionalTest.php
+++ b/tests/fixtures/tests/Functional/TestFunctionalTest.php
@@ -12,7 +12,7 @@ class TestFunctionalTest extends TestCase {
   /**
    * Tests something.
    */
-  public function testSomething() {
+  public function testSomething(): void {
     $this->addToAssertionCount(1);
   }
 
diff --git a/tests/fixtures/tests/Unit/TestUnitTest.php b/tests/fixtures/tests/Unit/TestUnitTest.php
index 90f0829..e6a2e63 100644
--- a/tests/fixtures/tests/Unit/TestUnitTest.php
+++ b/tests/fixtures/tests/Unit/TestUnitTest.php
@@ -12,7 +12,7 @@ class TestUnitTest extends TestCase {
   /**
    * Tests something.
    */
-  public function testSomething() {
+  public function testSomething(): void {
     $this->addToAssertionCount(1);
   }