diff --git a/module.json b/module.json
index 8056954..26ce18f 100644
--- a/module.json
+++ b/module.json
@@ -10,7 +10,8 @@
   ],
   "version": "3.3.9",
   "humhub": {
-    "minVersion": "1.18.0-beta.6"
+    "minVersion": "1.18.0-beta.6",
+    "maxVersion": "1.18"
   },
   "homepage": "https://github.com/humhub/mail",
   "authors": [