diff --git a/composer.json b/composer.json
index 77d4ee5..650d5cc 100644
--- a/composer.json
+++ b/composer.json
@@ -37,7 +37,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "~6.0 || ~7.0 || ~9.0",
-        "phpstan/phpstan": "1.8.*@dev",
+        "phpstan/phpstan": "1.9.*@dev",
         "phpstan/phpstan-strict-rules": "1.4.*@dev",
         "thecodingmachine/phpstan-strict-rules": "1.0.*@dev",
         "voku/phpstan-rules": "3.1.*@dev"