diff --git a/keyserver/src/responders/activity-responders.js b/keyserver/src/responders/activity-responders.js
index f8d9f2227..5f93bea93 100644
--- a/keyserver/src/responders/activity-responders.js
+++ b/keyserver/src/responders/activity-responders.js
@@ -1,57 +1,54 @@
 // @flow
 
 import t, { type TInterface, type TList } from 'tcomb';
 
 import {
   type UpdateActivityResult,
   type UpdateActivityRequest,
   type SetThreadUnreadStatusRequest,
   type SetThreadUnreadStatusResult,
   type ActivityUpdate,
+  activityUpdateValidator,
 } from 'lib/types/activity-types.js';
 import { tShape, tID } from 'lib/utils/validation-utils.js';
 
 import type { Viewer } from '../session/viewer.js';
 import {
   activityUpdater,
   setThreadUnreadStatus,
 } from '../updaters/activity-updaters.js';
 
 const activityUpdatesInputValidator: TList<Array<ActivityUpdate>> = t.list(
-  tShape({
-    focus: t.Bool,
-    threadID: tID,
-    latestMessage: t.maybe(tID),
-  }),
+  activityUpdateValidator,
 );
 
 export const updateActivityResponderInputValidator: TInterface<UpdateActivityRequest> =
   tShape<UpdateActivityRequest>({
     updates: activityUpdatesInputValidator,
   });
 
 async function updateActivityResponder(
   viewer: Viewer,
   request: UpdateActivityRequest,
 ): Promise<UpdateActivityResult> {
   return await activityUpdater(viewer, request);
 }
 
 export const setThreadUnreadStatusValidator: TInterface<SetThreadUnreadStatusRequest> =
   tShape<SetThreadUnreadStatusRequest>({
     threadID: tID,
     unread: t.Bool,
     latestMessage: t.maybe(tID),
   });
 async function threadSetUnreadStatusResponder(
   viewer: Viewer,
   request: SetThreadUnreadStatusRequest,
 ): Promise<SetThreadUnreadStatusResult> {
   return await setThreadUnreadStatus(viewer, request);
 }
 
 export {
   activityUpdatesInputValidator,
   updateActivityResponder,
   threadSetUnreadStatusResponder,
 };