diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 358c15d..4e764ba 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/vscode/devcontainers/php:8.3
+FROM mcr.microsoft.com/vscode/devcontainers/php:8.4
 
 # PHP memory limit
 RUN echo "memory_limit=768M" > /usr/local/etc/php/php.ini
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index e17d156..be5d940 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-version: ['7.4', '8.0', '8.1', '8.2', '8.3']
+        php-version: ['7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
     steps:
       - uses: actions/checkout@v4
       - name: Setup PHP
@@ -45,7 +45,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '8.3'
+          php-version: '8.4'
       - name: Install dependencies
         run: composer update --no-interaction --no-progress --ansi
       - name: Run static analysis
@@ -67,7 +67,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-version: ['7.4', '8.0', '8.1', '8.2', '8.3']
+        php-version: ['7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
         dependency-version: [prefer-lowest, prefer-stable]
     steps:
       - uses: actions/checkout@v4
diff --git a/.tool-versions b/.tool-versions
index d057894..9ec7880 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1 +1 @@
-php 8.3.13
+php 8.4.1