diff --git a/lib/handlers/dm-activity-handler.js b/lib/handlers/dm-activity-handler.js
--- a/lib/handlers/dm-activity-handler.js
+++ b/lib/handlers/dm-activity-handler.js
@@ -10,8 +10,8 @@
 import { useProcessAndSendDMOperation } from '../shared/dm-ops/process-dm-ops.js';
 import { getMostRecentNonLocalMessageID } from '../shared/id-utils.js';
 import { threadIsPending } from '../shared/thread-utils.js';
+import { threadSpecs } from '../shared/threads/thread-specs.js';
 import type { DMChangeThreadReadStatusOperation } from '../types/dm-ops.js';
-import { threadTypeIsThick } from '../types/thread-types-enum.js';
 import { useDispatchActionPromise } from '../utils/redux-promise-utils.js';
 import { useSelector } from '../utils/redux-utils.js';
 
@@ -107,7 +107,8 @@
       !viewerID ||
       !activeThread ||
       !activeThreadInfo ||
-      !threadTypeIsThick(activeThreadInfo.type) ||
+      !threadSpecs[activeThreadInfo.type].protocol
+        .threadActivityUpdatedByDMActivityHandler ||
       threadIsPending(activeThread)
     ) {
       return;
diff --git a/lib/shared/threads/protocols/dm-thread-protocol.js b/lib/shared/threads/protocols/dm-thread-protocol.js
--- a/lib/shared/threads/protocols/dm-thread-protocol.js
+++ b/lib/shared/threads/protocols/dm-thread-protocol.js
@@ -579,6 +579,8 @@
   messagesStoredOnServer: false,
 
   arePendingThreadsDescendantsOfGenesis: false,
+
+  threadActivityUpdatedByDMActivityHandler: true,
 });
 
 export { dmThreadProtocol };
diff --git a/lib/shared/threads/protocols/keyserver-thread-protocol.js b/lib/shared/threads/protocols/keyserver-thread-protocol.js
--- a/lib/shared/threads/protocols/keyserver-thread-protocol.js
+++ b/lib/shared/threads/protocols/keyserver-thread-protocol.js
@@ -375,6 +375,8 @@
   messagesStoredOnServer: true,
 
   arePendingThreadsDescendantsOfGenesis: true,
+
+  threadActivityUpdatedByDMActivityHandler: false,
 });
 
 function mediaIDIsKeyserverID(mediaID: string): boolean {
diff --git a/lib/shared/threads/thread-spec.js b/lib/shared/threads/thread-spec.js
--- a/lib/shared/threads/thread-spec.js
+++ b/lib/shared/threads/thread-spec.js
@@ -278,6 +278,9 @@
   +shouldPerformSideEffectsBeforeSendingMessage: boolean,
   +messagesStoredOnServer: boolean,
   +arePendingThreadsDescendantsOfGenesis: boolean,
+  // This flag is temporary. It should be deleted as a part of
+  // https://linear.app/comm/issue/ENG-10729/consider-merging-activity-handlers
+  +threadActivityUpdatedByDMActivityHandler: boolean,
 };
 
 export type ThreadSpec = {