diff --git a/composer.json b/composer.json
index 81cefc9..53a5e02 100644
--- a/composer.json
+++ b/composer.json
@@ -33,7 +33,7 @@
     "phpstan/phpstan-deprecation-rules": "^0.11",
     "phpstan/phpstan-phpunit": "^0.11",
     "phpstan/phpstan-strict-rules": "^0.11",
-    "phpunit/phpunit": "^7.5 || ^8.0",
+    "phpunit/phpunit": "^7.5.17",
     "squizlabs/php_codesniffer": "^3.4"
   },
   "config": {