diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Events/ExternalContact/ChangeExternalChatEvent.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Events/ExternalContact/ChangeExternalChatEvent.cs
index 3de689cd..2b353772 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Events/ExternalContact/ChangeExternalChatEvent.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Events/ExternalContact/ChangeExternalChatEvent.cs
@@ -1,4 +1,4 @@
-namespace SKIT.FlurlHttpClient.Wechat.Work.Events
+namespace SKIT.FlurlHttpClient.Wechat.Work.Events
 {
     /// <summary>
     /// <para>表示 EVENT.change_external_chat 或 INFO.change_external_chat 事件的数据。</para>
@@ -54,5 +54,17 @@
         /// </summary>
         [System.Xml.Serialization.XmlElement("MemChangeCnt", IsNullable = true)]
         public int? MemberChangedCount { get; set; }
+
+        /// <summary>
+        /// 获取或设置变更前的群成员版本号。
+        /// </summary>
+        [System.Xml.Serialization.XmlElement("LastMemVer", IsNullable = true)]
+        public string? LastMemberVersion { get; set; }
+
+        /// <summary>
+        /// 获取或设置变更后的群成员版本号。
+        /// </summary>
+        [System.Xml.Serialization.XmlElement("CurMemVer", IsNullable = true)]
+        public string? CurrentMemberVersion { get; set; }
     }
 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
index 472aac8b..4ff69e0c 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
@@ -500,6 +500,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
         /// <summary>
         /// <para>异步调用 [POST] /cgi-bin/externalcontact/customer_acquisition/list_link 接口。</para>
         /// <para>REF: https://developer.work.weixin.qq.com/document/path/97297 </para>
+        /// <para>REF: https://developer.work.weixin.qq.com/document/path/99484 </para>
         /// </summary>
         /// <param name="client"></param>
         /// <param name="request"></param>
@@ -520,6 +521,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
         /// <summary>
         /// <para>异步调用 [POST] /cgi-bin/externalcontact/customer_acquisition/get 接口。</para>
         /// <para>REF: https://developer.work.weixin.qq.com/document/path/97297 </para>
+        /// <para>REF: https://developer.work.weixin.qq.com/document/path/99484 </para>
         /// </summary>
         /// <param name="client"></param>
         /// <param name="request"></param>
@@ -640,6 +642,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
         /// <summary>
         /// <para>异步调用 [GET] /cgi-bin/externalcontact/customer_acquisition/statistic 接口。</para>
         /// <para>REF: https://developer.work.weixin.qq.com/document/path/97375 </para>
+        /// <para>REF: https://developer.work.weixin.qq.com/document/path/99483 </para>
         /// </summary>
         /// <param name="client"></param>
         /// <param name="request"></param>
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.cs
index 1bcbe84b..63b49aeb 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Models/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.cs
@@ -1,4 +1,4 @@
-namespace SKIT.FlurlHttpClient.Wechat.Work.Models
+namespace SKIT.FlurlHttpClient.Wechat.Work.Models
 {
     /// <summary>
     /// <para>表示 [POST] /cgi-bin/externalcontact/groupchat/get 接口的响应。</para>
@@ -149,6 +149,13 @@
                 [Newtonsoft.Json.JsonProperty("create_time")]
                 [System.Text.Json.Serialization.JsonPropertyName("create_time")]
                 public long CreateTimestamp { get; set; }
+
+                /// <summary>
+                /// 获取或设置当前群成员版本号。
+                /// </summary>
+                [Newtonsoft.Json.JsonProperty("member_version")]
+                [System.Text.Json.Serialization.JsonPropertyName("member_version")]
+                public string MemberVersion { get; set; } = default!;
             }
         }
 
diff --git a/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.json b/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.json
index 5e548118..63c64803 100644
--- a/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.json
+++ b/test/SKIT.FlurlHttpClient.Wechat.Work.UnitTests/ModelSamples/CgibinExternalContact/GroupChat/CgibinExternalContactGroupChatGetResponse.json
@@ -1,4 +1,4 @@
-{
+{
     "errcode": 0,
     "errmsg": "ok",
     "group_chat": {
@@ -37,6 +37,7 @@
             {
                 "userid": "pony"
             }
-        ]
+        ],
+        "member_version": "71217227bbd112ecfe3a49c482195cb4"
     }
 }