diff --git a/.github/workflows/emulator-tests.yml b/.github/workflows/emulator-tests.yml
index f23e370..9fdc8a2 100644
--- a/.github/workflows/emulator-tests.yml
+++ b/.github/workflows/emulator-tests.yml
@@ -18,7 +18,7 @@ on:
 
 jobs:
   tests:
-    name: PHP ${{ matrix.php }}
+    name: "PHP ${{ matrix.php }}, ${{ matrix.dependencies }} deps"
     runs-on: ubuntu-latest
 
     strategy:
@@ -27,6 +27,13 @@ jobs:
           - "8.1"
           - "8.2"
           - "8.3"
+        dependencies:
+          - "lowest"
+          - "highest"
+        include:
+          - php: "8.4"
+            composer-options: "--ignore-platform-reqs"
+            dependencies: "highest"
 
     steps:
       - name: Checkout code
@@ -40,6 +47,9 @@ jobs:
           coverage: xdebug
 
       - uses: "ramsey/composer-install@v3"
+        with:
+          composer-options: "${{ matrix.composer-options }}"
+          dependency-versions: "${{ matrix.dependencies }}"
 
       - name: Set Up Node
         uses: actions/setup-node@v4
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 5627729..fb8ef24 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -18,7 +18,7 @@ on:
 
 jobs:
   tests:
-    name: PHP ${{ matrix.php }}
+    name: "PHP ${{ matrix.php }}, ${{ matrix.dependencies }} deps"
     runs-on: ubuntu-latest
 
     strategy:
@@ -27,6 +27,13 @@ jobs:
           - "8.1"
           - "8.2"
           - "8.3"
+        dependencies:
+          - "lowest"
+          - "highest"
+        include:
+          - php: "8.4"
+            composer-options: "--ignore-platform-reqs"
+            dependencies: "highest"
 
     steps:
       - name: Checkout code
@@ -40,6 +47,9 @@ jobs:
           coverage: xdebug
 
       - uses: "ramsey/composer-install@v3"
+        with:
+          composer-options: "${{ matrix.composer-options }}"
+          dependency-versions: "${{ matrix.dependencies }}"
 
       - name: Setup Problem Matchers
         run: |
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cdbe2ff..5713630 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+* Added support for PHP 8.4
+  ([#61](https://github.com/kreait/firebase-tokens-php/pull/61))
+
 ## 5.1.0 - 2024-05-10
 
 * Restored support for PHP 8.1
diff --git a/composer.json b/composer.json
index 15644d5..05f1394 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
         }
     ],
     "require": {
-        "php": "~8.1.0 || ~8.2.0 || ~8.3.0",
+        "php": "~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
         "ext-json": "*",
         "ext-openssl": "*",
         "beste/clock": "^3.0",