diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b3741df..fd15977 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,35 +5,45 @@ on: [push]
 jobs:
   composer:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php: [ 8.1, 8.2, 8.3 ]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Cache Composer dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: /tmp/composer-cache
-          key: ${{ runner.os }}-${{ hashFiles('**/composer.lock') }}
+          key: ${{ runner.os }}-${{ matrix.php }}-${{ hashFiles('**/composer.lock') }}
 
-      - uses: php-actions/composer@v6
+      - name: Composer install
+        uses: php-actions/composer@v6
+        with:
+          php_version: ${{ matrix.php }}
+          php_extensions: pcntl
 
       - name: Archive build
         run: mkdir /tmp/github-actions/ && tar -cvf /tmp/github-actions/build.tar ./
 
       - name: Upload build archive for test runners
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
-          name: build-artifact
+          name: build-artifact-${{ matrix.php }}
           path: /tmp/github-actions
 
   phpstan:
     runs-on: ubuntu-latest
-    needs: [composer]
+    needs: [ composer ]
+    strategy:
+      matrix:
+        php: [ 8.1, 8.2, 8.3 ]
 
     steps:
-      - uses: actions/download-artifact@v2
+      - uses: actions/download-artifact@v4
         with:
-          name: build-artifact
+          name: build-artifact-${{ matrix.php }}
           path: /tmp/github-actions
 
       - name: Extract build archive
@@ -42,4 +52,68 @@ jobs:
       - name: PHP Static Analysis
         uses: php-actions/phpstan@v3
         with:
+          php_version: ${{ matrix.php }}
           path: src/
+          level: 6
+
+  phpmd:
+    runs-on: ubuntu-latest
+    needs: [ composer ]
+    strategy:
+      matrix:
+        php: [ 8.1, 8.2, 8.3 ]
+
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: build-artifact-${{ matrix.php }}
+          path: /tmp/github-actions
+
+      - name: Extract build archive
+        run: tar -xvf /tmp/github-actions/build.tar ./
+
+      - name: PHP Mess Detector
+        uses: php-actions/phpmd@v1
+        with:
+          php_version: ${{ matrix.php }}
+          path: src/
+          output: text
+          ruleset: phpmd.xml
+
+  phpcs:
+    runs-on: ubuntu-latest
+    needs: [ composer ]
+    strategy:
+      matrix:
+        php: [ 8.1, 8.2, 8.3 ]
+
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: build-artifact-${{ matrix.php }}
+          path: /tmp/github-actions
+
+      - name: Extract build archive
+        run: tar -xvf /tmp/github-actions/build.tar ./
+
+      - name: PHP Code Sniffer
+        uses: php-actions/phpcs@v1
+        with:
+          php_version: ${{ matrix.php }}
+          path: src/
+          standard: phpcs.xml
+
+  remove_old_artifacts:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Remove old artifacts for prior workflow runs on this repository
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          gh api "/repos/${{ github.repository }}/actions/artifacts?name=build-artifact" | jq ".artifacts[] | select(.name | startswith(\"build-artifact\")) | .id" > artifact-id-list.txt
+          while read id
+          do
+            echo -n "Deleting artifact ID $id ... "
+            gh api --method DELETE /repos/${{ github.repository }}/actions/artifacts/$id && echo "Done"
+          done <artifact-id-list.txt