diff --git a/projects/ucap-webmessenger-protocol-group/src/lib/models/group-update.ts b/projects/ucap-webmessenger-protocol-group/src/lib/models/group-update.ts
index ba28ad7e..996b5f5a 100644
--- a/projects/ucap-webmessenger-protocol-group/src/lib/models/group-update.ts
+++ b/projects/ucap-webmessenger-protocol-group/src/lib/models/group-update.ts
@@ -15,7 +15,7 @@ export interface GroupUpdateRequest extends ProtocolRequest {
   // 1: 동료그룹이름(s)
   groupName: string;
   // 2n: 사용자SEQ(n)...
-  userSeqs: [];
+  userSeqs: number[];
 }
 
 export interface GroupUpdateResponse extends ProtocolResponse {
@@ -24,7 +24,7 @@ export interface GroupUpdateResponse extends ProtocolResponse {
   // 1: 동료그룹이름(s)
   groupName: string;
   // 2n: 사용자SEQ(n)...
-  userSeqs: [];
+  userSeqs: number[];
 }
 
 export const encodeGroupUpdate: ProtocolEncoder<GroupUpdateRequest> = (
@@ -35,7 +35,7 @@ export const encodeGroupUpdate: ProtocolEncoder<GroupUpdateRequest> = (
   bodyList.push(
     { type: PacketBodyValue.Integer, value: req.groupSeq },
     { type: PacketBodyValue.String, value: req.groupName },
-    { type: PacketBodyValue.String, value: req.userSeqs.join() }
+    { type: PacketBodyValue.String, value: req.userSeqs.join(',') }
   );
 
   return bodyList;
@@ -44,9 +44,9 @@ export const encodeGroupUpdate: ProtocolEncoder<GroupUpdateRequest> = (
 export const decodeGroupUpdate: ProtocolDecoder<GroupUpdateResponse> = (
   message: ProtocolMessage
 ) => {
-  let userSeqArray: Array<number> = [];
+  let userSeqArray: number[] = [];
   if (message.bodyList.length > 2 && !message.bodyList[2].empty()) {
-    userSeqArray = message.bodyList[2].split(',').map(v => Number(v));
+    userSeqArray = message.bodyList[2].split(',').map((v: any) => Number(v));
   }
 
   return {
@@ -78,7 +78,7 @@ export const encodeGroupUpdate2: ProtocolEncoder<GroupUpdateRequest> = (
 export const decodeGroupUpdate2: ProtocolDecoder<GroupUpdateResponse> = (
   message: ProtocolMessage
 ) => {
-  let userSeqArray: Array<number> = [];
+  let userSeqArray: number[] = [];
   if (message.bodyList.length > 2) {
     userSeqArray = message.bodyList.slice(2);
   }