diff --git a/OpenAPI/TS28623_GenericNrm.yaml b/OpenAPI/TS28623_GenericNrm.yaml
index 16385e044188b3b64aa9d539a629a3fdcad0e166..24855fc4b3cadc6ead243b1ddbfd8185a3afa602 100755
--- a/OpenAPI/TS28623_GenericNrm.yaml
+++ b/OpenAPI/TS28623_GenericNrm.yaml
@@ -331,7 +331,6 @@ components:
                 maximum: 31
     NpnId-Type:
       type: object
-      description: This describes the PLMN id, CAG ID list or the NID of the SNPN within the PLMN.
       properties:
         plmnId:
           $ref: 'TS28623_ComDefs.yaml#/components/schemas/PlmnId'
@@ -339,10 +338,17 @@ components:
           type: array
           items:
             type: string
+          minItems: 1
+          maxItems: 256  
         nIDList:
           type: array
           items:
             $ref: 'TS28623_ComDefs.yaml#/components/schemas/Nid'
+          minItems: 1
+          maxItems: 16
+      oneOf:
+        - required: [plmnId, cAGIdList]
+        - required: [plmnId, nIDList]
 
 #-------- Definition of abstract IOC Top -----------------------------------------