diff --git a/.github/workflows/coding-standards.yml b/.github/workflows/coding-standards.yml
index 9ffb014..6ae6269 100644
--- a/.github/workflows/coding-standards.yml
+++ b/.github/workflows/coding-standards.yml
@@ -21,6 +21,7 @@ jobs:
         php-version:
           - "7.4"
           - "8.0"
+          - "8.1"
         operating-system:
           - "ubuntu-latest"
 
diff --git a/.github/workflows/mutation-tests.yml b/.github/workflows/mutation-tests.yml
index 0401223..9e7bd65 100644
--- a/.github/workflows/mutation-tests.yml
+++ b/.github/workflows/mutation-tests.yml
@@ -21,6 +21,7 @@ jobs:
         php-version:
           - "7.4"
           - "8.0"
+          - "8.1"
         operating-system:
           - "ubuntu-latest"
 
diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index ac80f97..be2b672 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -21,6 +21,7 @@ jobs:
         php-version:
           - "7.4"
           - "8.0"
+          - "8.1"
         operating-system:
           - "ubuntu-latest"
 
diff --git a/.github/workflows/psalm.yml b/.github/workflows/psalm.yml
index ca9d0ff..d9adca4 100644
--- a/.github/workflows/psalm.yml
+++ b/.github/workflows/psalm.yml
@@ -21,6 +21,7 @@ jobs:
         php-version:
           - "7.4"
           - "8.0"
+          - "8.1"
         operating-system:
           - "ubuntu-latest"
 
diff --git a/composer.json b/composer.json
index 2bb0e42..6b9e6ea 100644
--- a/composer.json
+++ b/composer.json
@@ -16,11 +16,12 @@
         }
     ],
     "require": {
-        "php": "^7.4|^8.0"
+        "php": "^7.4|>=8.0"
     },
     "require-dev": {
         "icanhazstring/composer-unused": "^0.7.5",
         "infection/infection": "^0.25",
+        "phpcompatibility/php-compatibility": "^9.3",
         "phpro/grumphp": "^1.0",
         "phpstan/phpstan": "^1.0",
         "phpunit/phpunit": "^8.0 || ^9.0",
diff --git a/phpcs.xml.dist b/phpcs.xml.dist
index 42e9edf..45d683d 100644
--- a/phpcs.xml.dist
+++ b/phpcs.xml.dist
@@ -6,6 +6,11 @@
     <arg value="p"/>
     <arg name="colors"/>
 
+    <!-- php compatibility checker config -->
+    <rule ref="PHPCompatibility"/>
+    <config name="installed_paths" value="vendor/phpcompatibility/php-compatibility" />
+    <config name="testVersion" value="7.4-"/>
+
     <!-- inherit rules from: -->
     <rule ref="PSR12"/>
     <rule ref="Generic.Arrays.DisallowLongArraySyntax"/>