diff --git a/assets/schema.json b/assets/schema.json
index a00cd6e..252fb24 100644
--- a/assets/schema.json
+++ b/assets/schema.json
@@ -146,10 +146,7 @@
             "type": "string"
           },
           "groupId": {
-            "anyOf": [
-              {"type": "string"},
-              {"type": "null"}
-            ]
+            "type": ["string", "null"]
           },
           "playerIds": {
             "type": "array",