diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 76a2d355..960f491a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,7 +16,7 @@ jobs:
         runs-on: ubuntu-22.04
         strategy:
             matrix:
-                php-version: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
+                php-version: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
 
         steps:
             - name: Checkout
@@ -59,7 +59,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php-version: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
+                php-version: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
 
         steps:
             - name: Checkout
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed390901..5668ff71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 ## x.y.z
 
 ### Added
+- Add official support for PHP 8.4 (#657)
 - Support arithmetic operators in CSS function arguments (#607)
 - Add support for inserting an item in a CSS list (#545)
 - Add a class diagram to the README (#482)