diff --git a/composer.json b/composer.json
index 02cfd9d..898c90a 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
         "ext-mbstring": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.4|^6.5.13|^5.7.27|^4.8.36",
+        "phpunit/phpunit": "^7.4||^6.5.13||^5.7.27||^4.8.36",
         "vimeo/psalm": "^3.0.11",
         "friendsofphp/php-cs-fixer": "^2.13",
         "infection/infection": "^0.12.0"