diff --git a/APIs/schemas/constraint_set.json b/APIs/schemas/constraint_set.json
index ab439d3..372361d 100644
--- a/APIs/schemas/constraint_set.json
+++ b/APIs/schemas/constraint_set.json
@@ -23,8 +23,21 @@
     }
   },
   "patternProperties": {
-    "^urn:x-nmos:cap:(?!meta:)": {
+    "^urn:[a-z0-9][a-z0-9-]+:cap:(?!meta:)": {
       "$ref": "param_constraint.json"
-    }
+    },
+    "^urn:(?!x-nmos)[a-z0-9][a-z0-9-]+:cap:meta:": {
+      "oneOf": [
+          {
+            "type": [ "boolean", "integer", "number", "string", "null" ]
+          },
+          {
+            "type": "array",
+            "items": {
+                "type": [ "boolean", "integer", "number", "string" ]
+            }
+          }
+      ]
+   }
   }
 }
diff --git a/APIs/schemas/constraints_supported.json b/APIs/schemas/constraints_supported.json
index b1d3935..aa11d97 100644
--- a/APIs/schemas/constraints_supported.json
+++ b/APIs/schemas/constraints_supported.json
@@ -28,7 +28,7 @@
             ]
           },
           {
-            "pattern": "^urn:x-nmos:cap:"
+            "pattern": "^urn:[a-z0-9][a-z0-9-]+:cap:"
           }
         ]
       },