diff --git a/.github/workflows/php-dev.yml b/.github/workflows/php-dev.yml
index 382d042a..e1a0b25d 100644
--- a/.github/workflows/php-dev.yml
+++ b/.github/workflows/php-dev.yml
@@ -29,7 +29,7 @@ concurrency:
 permissions: {}
 
 env:
-  PHP_VERSION_LATEST: "8.4"
+  PHP_VERSION_LATEST: "8.5"
   PHP_PROJECT_EXT: dom,filter,json,libxml,simplexml  # via `composer info -pt`
 
 jobs:
@@ -44,7 +44,8 @@ jobs:
           - "macos-latest"
           - "windows-latest"
         php:
-          - "8.4"   # highest supported
+          - "8.5"   # highest supported
+          - "8.4"
           - "8.3"
           - "8.2"
           - "8.1"   # lowest supported
diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index fce5d4c7..abbd7866 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -21,7 +21,7 @@ permissions: {}
 
 env:
   PHP_VERSION_LOWEST: "8.1"  # lowest supported
-  PHP_VERSION_LATEST: "8.4"  # highest supported
+  PHP_VERSION_LATEST: "8.5"  # highest supported
   PHP_PROJECT_EXT: dom,json,libxml,simplexml  # via `composer info -pt`
   REPORTS_DIR: CI_reports
   TESTS_REPORTS_ARTIFACT: tests-reports
@@ -54,7 +54,8 @@ jobs:
       matrix:
         os: [ "ubuntu-latest", "windows-latest", "macos-latest" ]
         php:
-          - "8.4"   # highest supported
+          - "8.5"   # highest supported
+          - "8.4"
           - "8.3"
           - "8.2"
           - "8.1"   # lowest supported
@@ -152,7 +153,7 @@ jobs:
       matrix:
         include:
           - # highest supported
-            php: "8.4"
+            php: "8.5"
             dependencies: "highest"
           - # lowest supported
             php: "8.1"
diff --git a/HISTORY.md b/HISTORY.md
index 446228f4..9e2a105c 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -6,6 +6,12 @@ All notable changes to this project will be documented in this file.
 
 <!-- add unreleased items here -->
 
+* Added
+  * Officially support PHP 8.5 ([#566] via [#574])
+
+[#566]: https://github.com/CycloneDX/cyclonedx-php-library/issues/566
+[#574]: https://github.com/CycloneDX/cyclonedx-php-library/pull/574
+
 ## 3.9.0 - 2025-12-02
 
 * Added
diff --git a/tools/composer-require-checker/composer.json b/tools/composer-require-checker/composer.json
index 8af4ab26..ecec7392 100644
--- a/tools/composer-require-checker/composer.json
+++ b/tools/composer-require-checker/composer.json
@@ -6,7 +6,7 @@
         "php": "^8.1.31"
     },
     "require-dev": {
-        "maglnet/composer-require-checker": "4.7.1||4.16.1",
+        "maglnet/composer-require-checker": "4.7.1||4.16.1||4.19.0",
         "roave/security-advisories": "dev-latest"
     },
     "prefer-stable": true,
diff --git a/tools/php-cs-fixer/composer.json b/tools/php-cs-fixer/composer.json
index 02d9c1ac..cc723424 100644
--- a/tools/php-cs-fixer/composer.json
+++ b/tools/php-cs-fixer/composer.json
@@ -6,7 +6,7 @@
         "php": "^8.1.31"
     },
     "require-dev": {
-        "friendsofphp/php-cs-fixer": "3.91.0",
+        "friendsofphp/php-cs-fixer": "3.91.2",
         "roave/security-advisories": "dev-latest"
     },
     "prefer-stable": true,
diff --git a/tools/phpunit/composer.json b/tools/phpunit/composer.json
index 2715cae8..09173c99 100644
--- a/tools/phpunit/composer.json
+++ b/tools/phpunit/composer.json
@@ -6,7 +6,7 @@
         "php": "^8.1.31"
     },
     "require-dev": {
-        "phpunit/phpunit": "10.5.45||11.5.7||12.0.2",
+        "phpunit/phpunit": "10.5.45||11.5.7||12.4.5",
         "roave/security-advisories": "dev-latest"
     },
     "prefer-stable": true,