diff --git a/apps/ios/SimpleXChat/ChatTypes.swift b/apps/ios/SimpleXChat/ChatTypes.swift
index e066e1fba0..9a82c912dd 100644
--- a/apps/ios/SimpleXChat/ChatTypes.swift
+++ b/apps/ios/SimpleXChat/ChatTypes.swift
@@ -15,6 +15,9 @@ public let CREATE_MEMBER_CONTACT_VERSION = 2
 // version to receive reports (MCReport)
 public let REPORTS_VERSION = 12
 
+// support group knocking (MsgScope)
+public let GROUP_KNOCKING_VERSION = 15
+
 public let contentModerationPostLink = URL(string: "https://simplex.chat/blog/20250114-simplex-network-large-groups-privacy-preserving-content-moderation.html#preventing-server-abuse-without-compromising-e2e-encryption")!
 
 public struct User: Identifiable, Decodable, UserLike, NamedChat, Hashable {
@@ -1346,11 +1349,19 @@ public enum ChatInfo: Identifiable, Decodable, NamedChat, Hashable {
                 return nil
             case let .group(groupInfo, groupChatScope):
                 if groupInfo.membership.memberActive {
-                    if groupChatScope == nil {
+                    switch(groupChatScope) {
+                    case .none:
                         if groupInfo.membership.memberPending { return ("reviewed by admins", "Please contact group admin.") }
                         if groupInfo.membership.memberRole == .observer { return ("you are observer", "Please contact group admin.") }
+                        return nil
+                    case let .some(.memberSupport(groupMember_: .some(supportMember))):
+                        if supportMember.versionRange.maxVersion < GROUP_KNOCKING_VERSION && !supportMember.memberPending {
+                            return ("member has old version", nil)
+                        }
+                        return nil
+                    case .some(.memberSupport(groupMember_: .none)):
+                        return nil
                     }
-                    return nil
                 } else {
                     switch groupInfo.membership.memberStatus {
                     case .memRejected: return ("request to join rejected", nil)
diff --git a/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/ChatModel.kt b/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/ChatModel.kt
index 7bd9a1844a..270b3a73b2 100644
--- a/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/ChatModel.kt
+++ b/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/ChatModel.kt
@@ -1500,15 +1500,29 @@ sealed class ChatInfo: SomeChat, NamedChat {
         }
         is Group -> {
           if (groupInfo.membership.memberActive) {
-            if (groupChatScope == null) {
-              if (groupInfo.membership.memberPending) {
-                return generalGetString(MR.strings.reviewed_by_admins) to generalGetString(MR.strings.observer_cant_send_message_desc)
-              }
-              if (groupInfo.membership.memberRole == GroupMemberRole.Observer) {
-                return generalGetString(MR.strings.observer_cant_send_message_title) to generalGetString(MR.strings.observer_cant_send_message_desc)
+            when (groupChatScope) {
+              null -> {
+                if (groupInfo.membership.memberPending) {
+                  return generalGetString(MR.strings.reviewed_by_admins) to generalGetString(MR.strings.observer_cant_send_message_desc)
+                }
+                if (groupInfo.membership.memberRole == GroupMemberRole.Observer) {
+                  return generalGetString(MR.strings.observer_cant_send_message_title) to generalGetString(MR.strings.observer_cant_send_message_desc)
+                }
+                return null
               }
+              is GroupChatScopeInfo.MemberSupport ->
+                if (groupChatScope.groupMember_ != null) {
+                  if (
+                    groupChatScope.groupMember_.versionRange.maxVersion < GROUP_KNOCKING_VERSION
+                    && !groupChatScope.groupMember_.memberPending
+                  ) {
+                    return generalGetString(MR.strings.cant_send_message_member_has_old_version) to null
+                  }
+                  return null
+                } else {
+                  return null
+                }
             }
-            return null
           } else {
             return when (groupInfo.membership.memberStatus) {
               GroupMemberStatus.MemRejected -> generalGetString(MR.strings.cant_send_message_rejected) to null
@@ -2005,7 +2019,8 @@ data class GroupMember (
   val memberContactId: Long? = null,
   val memberContactProfileId: Long,
   var activeConn: Connection? = null,
-  val supportChat: GroupSupportChat? = null
+  val supportChat: GroupSupportChat? = null,
+  val memberChatVRange: VersionRange
 ): NamedChat {
   val id: String get() = "#$groupId @$groupMemberId"
   val ready get() = activeConn?.connStatus == ConnStatus.Ready
@@ -2119,6 +2134,8 @@ data class GroupMember (
         && userRole >= GroupMemberRole.Moderator && userRole >= memberRole && groupInfo.membership.memberActive
   }
 
+  val versionRange: VersionRange = activeConn?.peerChatVRange ?: memberChatVRange
+
   val memberIncognito = memberProfile.profileId != memberContactProfileId
 
   companion object {
@@ -2136,7 +2153,8 @@ data class GroupMember (
       memberProfile = LocalProfile.sampleData,
       memberContactId = 1,
       memberContactProfileId = 1L,
-      activeConn = Connection.sampleData
+      activeConn = Connection.sampleData,
+      memberChatVRange = VersionRange(minVersion = 1, maxVersion = 15)
     )
   }
 }
diff --git a/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/SimpleXAPI.kt b/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/SimpleXAPI.kt
index 12c93888ee..8378b6fa3b 100644
--- a/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/SimpleXAPI.kt
+++ b/apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/model/SimpleXAPI.kt
@@ -58,6 +58,9 @@ typealias ChatCtrl = Long
 // version range that supports establishing direct connection with a group member (xGrpDirectInvVRange in core)
 val CREATE_MEMBER_CONTACT_VERSION = 2
 
+// support group knocking (MsgScope)
+val GROUP_KNOCKING_VERSION = 15
+
 enum class CallOnLockScreen {
   DISABLE,
   SHOW,
diff --git a/apps/multiplatform/common/src/commonMain/resources/MR/base/strings.xml b/apps/multiplatform/common/src/commonMain/resources/MR/base/strings.xml
index 6198207991..b130970467 100644
--- a/apps/multiplatform/common/src/commonMain/resources/MR/base/strings.xml
+++ b/apps/multiplatform/common/src/commonMain/resources/MR/base/strings.xml
@@ -526,6 +526,7 @@
   <string name="cant_send_message_generic">can\'t send messages</string>
   <string name="you_are_observer">you are observer</string>
   <string name="reviewed_by_admins">reviewed by admins</string>
+  <string name="cant_send_message_member_has_old_version">member has old version</string>
 
   <!-- Images - chat.simplex.app.views.chat.item.CIImageView.kt -->
   <string name="image_descr">Image</string>