diff --git a/composer.json b/composer.json
index 7383829..451463b 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,7 @@
     "require": {
         "php": "~7.0.0 || ~7.1.0",
 
-        "phplist/phplist4-core": "^4.0.0-dev",
+        "phplist/phplist4-core": "4.0.x-dev",
 
         "roave/security-advisories": "dev-master"
     },
@@ -50,7 +50,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "4.0.0-dev"
+            "dev-master": "4.0.x-dev"
         }
     }
 }