diff --git a/.github/workflows/static.yml b/.github/workflows/static.yml
index 9d5539c..ae04dd5 100644
--- a/.github/workflows/static.yml
+++ b/.github/workflows/static.yml
@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -24,7 +24,7 @@ jobs:
           update: true
 
       - name: Install Dependencies
-        uses: nick-invision/retry@v3
+        uses: nick-fields/retry@v3
         with:
           timeout_minutes: 5
           max_attempts: 5
@@ -35,11 +35,11 @@ jobs:
 
   psalm:
     name: Psalm
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -51,7 +51,7 @@ jobs:
           update: true
 
       - name: Install Dependencies
-        uses: nick-invision/retry@v3
+        uses: nick-fields/retry@v3
         with:
           timeout_minutes: 5
           max_attempts: 5
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 0183705..10a22e2 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -12,11 +12,11 @@ jobs:
 
     strategy:
       matrix:
-        php: ['7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
+        php: ['7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5']
 
     steps:
       - name: Checkout Code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
@@ -31,7 +31,7 @@ jobs:
         run: echo "::add-matcher::${{ runner.tool_cache }}/phpunit.json"
 
       - name: Install Dependencies
-        uses: nick-invision/retry@v3
+        uses: nick-fields/retry@v3
         with:
           timeout_minutes: 5
           max_attempts: 5
diff --git a/composer.json b/composer.json
index 3526076..763ef2f 100644
--- a/composer.json
+++ b/composer.json
@@ -50,7 +50,8 @@
             "DOCKER_BUILDKIT=1 docker build -t cloudevents/sdk-php:8.1-tests -f hack/8.1.Dockerfile hack",
             "DOCKER_BUILDKIT=1 docker build -t cloudevents/sdk-php:8.2-tests -f hack/8.2.Dockerfile hack",
             "DOCKER_BUILDKIT=1 docker build -t cloudevents/sdk-php:8.3-tests -f hack/8.3.Dockerfile hack",
-            "DOCKER_BUILDKIT=1 docker build -t cloudevents/sdk-php:8.4-tests -f hack/8.4.Dockerfile hack"
+            "DOCKER_BUILDKIT=1 docker build -t cloudevents/sdk-php:8.4-tests -f hack/8.4.Dockerfile hack",
+            "DOCKER_BUILDKIT=1 docker build -t cloudevents/sdk-php:8.5-tests -f hack/8.5.Dockerfile hack"
         ],
         "tests-docker": [
             "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:7.4-tests --coverage-html=coverage",
@@ -58,7 +59,8 @@
             "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.1-tests",
             "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.2-tests",
             "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.3-tests",
-            "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.4-tests"
+            "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.4-tests",
+            "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.5-tests"
         ]
     },
     "scripts-descriptions": {
diff --git a/hack/8.5.Dockerfile b/hack/8.5.Dockerfile
new file mode 100644
index 0000000..910b716
--- /dev/null
+++ b/hack/8.5.Dockerfile
@@ -0,0 +1,22 @@
+FROM php:8.5-alpine
+
+LABEL org.opencontainers.image.url="https://github.com/cloudevents/sdk-php/tree/main/hack/8.5.Dockerfile" \
+      org.opencontainers.image.documentation="https://github.com/cloudevents/sdk-php/tree/main/hack/README.md" \
+      org.opencontainers.image.source="https://github.com/cloudevents/sdk-php" \
+      org.opencontainers.image.vendor="CloudEvent" \
+      org.opencontainers.image.title="PHP 8.5" \
+      org.opencontainers.image.description="PHP 8.5 test environment for cloudevents/sdk-php"
+
+COPY --chown=www-data:www-data install-composer /usr/local/bin/install-composer
+RUN chmod +x /usr/local/bin/install-composer \
+    && /usr/local/bin/install-composer \
+    && rm /usr/local/bin/install-composer
+
+RUN apk update \
+    && apk --no-cache upgrade \
+    && apk add --no-cache bash ca-certificates git libzip-dev \
+    && rm -rf /var/www/html /tmp/pear \
+    && chown -R www-data:www-data /var/www
+
+WORKDIR /var/www
+ENTRYPOINT ["/var/www/vendor/bin/phpunit"]