diff --git a/composer.json b/composer.json
index 658dce4..b6cc4e3 100644
--- a/composer.json
+++ b/composer.json
@@ -49,14 +49,16 @@
             "DOCKER_BUILDKIT=1 docker build -t cloudevents/sdk-php:8.0-tests -f hack/8.0.Dockerfile hack",
             "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:8.3-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"
         ],
         "tests-docker": [
             "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:7.4-tests --coverage-html=coverage",
             "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.0-tests",
             "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:8.3-tests",
+            "docker run -it -v $(pwd):/var/www cloudevents/sdk-php:8.4-tests"
         ]
     },
     "scripts-descriptions": {
diff --git a/hack/8.3.Dockerfile b/hack/8.3.Dockerfile
index f32111f..e521ba5 100644
--- a/hack/8.3.Dockerfile
+++ b/hack/8.3.Dockerfile
@@ -1,4 +1,4 @@
-FROM php:8.3-rc-alpine
+FROM php:8.3-alpine
 
 LABEL org.opencontainers.image.url="https://github.com/cloudevents/sdk-php/tree/main/hack/8.3.Dockerfile" \
       org.opencontainers.image.documentation="https://github.com/cloudevents/sdk-php/tree/main/hack/README.md" \
diff --git a/hack/8.4.Dockerfile b/hack/8.4.Dockerfile
new file mode 100644
index 0000000..9fcdc49
--- /dev/null
+++ b/hack/8.4.Dockerfile
@@ -0,0 +1,22 @@
+FROM php:8.4-alpine
+
+LABEL org.opencontainers.image.url="https://github.com/cloudevents/sdk-php/tree/main/hack/8.4.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 8.4" \
+      org.opencontainers.image.description="PHP 8.4 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"]