diff --git a/lib/actions/activity-actions.js b/lib/actions/activity-actions.js
--- a/lib/actions/activity-actions.js
+++ b/lib/actions/activity-actions.js
@@ -5,9 +5,14 @@
   ActivityUpdateSuccessPayload,
   SetThreadUnreadStatusPayload,
   SetThreadUnreadStatusRequest,
-  SetThreadUnreadStatusResult,
 } from '../types/activity-types.js';
-import type { CallServerEndpoint } from '../utils/call-server-endpoint.js';
+import { extractKeyserverIDFromID } from '../utils/action-utils.js';
+import type { CallKeyserverEndpoint } from '../utils/keyserver-call';
+import { useKeyserverCall } from '../utils/keyserver-call.js';
+
+export type UpdateActivityInput = {
+  +activityUpdates: $ReadOnlyArray<ActivityUpdate>,
+};
 
 const updateActivityActionTypes = Object.freeze({
   started: 'UPDATE_ACTIVITY_STARTED',
@@ -16,22 +21,42 @@
 });
 const updateActivity =
   (
-    callServerEndpoint: CallServerEndpoint,
-  ): ((
-    activityUpdates: $ReadOnlyArray<ActivityUpdate>,
-  ) => Promise<ActivityUpdateSuccessPayload>) =>
-  async activityUpdates => {
-    const response = await callServerEndpoint('update_activity', {
-      updates: activityUpdates,
-    });
+    callKeyserverEndpoint: CallKeyserverEndpoint,
+  ): ((input: UpdateActivityInput) => Promise<ActivityUpdateSuccessPayload>) =>
+  async input => {
+    const { activityUpdates } = input;
+    const requests = {};
+    for (const update of activityUpdates) {
+      const keyserverID = extractKeyserverIDFromID(update.threadID);
+      if (!requests[keyserverID]) {
+        requests[keyserverID] = { updates: [] };
+      }
+      requests[keyserverID].updates.push(update);
+    }
+
+    const responses = await callKeyserverEndpoint('update_activity', requests);
+
+    let unfocusedToUnread = [];
+    for (const keyserverID in responses) {
+      unfocusedToUnread = unfocusedToUnread.concat(
+        responses[keyserverID].unfocusedToUnread,
+      );
+    }
+
     return {
       activityUpdates,
       result: {
-        unfocusedToUnread: response.unfocusedToUnread,
+        unfocusedToUnread,
       },
     };
   };
 
+function useUpdateActivity(): (
+  input: UpdateActivityInput,
+) => Promise<ActivityUpdateSuccessPayload> {
+  return useKeyserverCall(updateActivity);
+}
+
 const setThreadUnreadStatusActionTypes = Object.freeze({
   started: 'SET_THREAD_UNREAD_STATUS_STARTED',
   success: 'SET_THREAD_UNREAD_STATUS_SUCCESS',
@@ -39,24 +64,33 @@
 });
 const setThreadUnreadStatus =
   (
-    callServerEndpoint: CallServerEndpoint,
+    callKeyserverEndpoint: CallKeyserverEndpoint,
   ): ((
-    request: SetThreadUnreadStatusRequest,
+    input: SetThreadUnreadStatusRequest,
   ) => Promise<SetThreadUnreadStatusPayload>) =>
-  async request => {
-    const response: SetThreadUnreadStatusResult = await callServerEndpoint(
+  async input => {
+    const keyserverID = extractKeyserverIDFromID(input.threadID);
+    const requests = { [keyserverID]: input };
+
+    const responses = await callKeyserverEndpoint(
       'set_thread_unread_status',
-      request,
+      requests,
     );
     return {
-      resetToUnread: response.resetToUnread,
-      threadID: request.threadID,
+      resetToUnread: responses[keyserverID].resetToUnread,
+      threadID: input.threadID,
     };
   };
 
+function useSetThreadUnreadStatus(): (
+  request: SetThreadUnreadStatusRequest,
+) => Promise<SetThreadUnreadStatusPayload> {
+  return useKeyserverCall(setThreadUnreadStatus);
+}
+
 export {
   updateActivityActionTypes,
-  updateActivity,
+  useUpdateActivity,
   setThreadUnreadStatusActionTypes,
-  setThreadUnreadStatus,
+  useSetThreadUnreadStatus,
 };
diff --git a/lib/hooks/toggle-unread-status.js b/lib/hooks/toggle-unread-status.js
--- a/lib/hooks/toggle-unread-status.js
+++ b/lib/hooks/toggle-unread-status.js
@@ -3,7 +3,7 @@
 import * as React from 'react';
 
 import {
-  setThreadUnreadStatus,
+  useSetThreadUnreadStatus,
   setThreadUnreadStatusActionTypes,
 } from '../actions/activity-actions.js';
 import type {
@@ -11,10 +11,7 @@
   SetThreadUnreadStatusRequest,
 } from '../types/activity-types.js';
 import type { ThreadInfo } from '../types/thread-types.js';
-import {
-  useDispatchActionPromise,
-  useServerCall,
-} from '../utils/action-utils.js';
+import { useDispatchActionPromise } from '../utils/action-utils.js';
 
 function useToggleUnreadStatus(
   threadInfo: ThreadInfo,
@@ -25,9 +22,7 @@
   const { currentUser } = threadInfo;
   const boundSetThreadUnreadStatus: (
     request: SetThreadUnreadStatusRequest,
-  ) => Promise<SetThreadUnreadStatusPayload> = useServerCall(
-    setThreadUnreadStatus,
-  );
+  ) => Promise<SetThreadUnreadStatusPayload> = useSetThreadUnreadStatus();
   const toggleUnreadStatus = React.useCallback(() => {
     const request = {
       threadID: threadInfo.id,
diff --git a/lib/socket/activity-handler.react.js b/lib/socket/activity-handler.react.js
--- a/lib/socket/activity-handler.react.js
+++ b/lib/socket/activity-handler.react.js
@@ -6,16 +6,13 @@
 
 import {
   updateActivityActionTypes,
-  updateActivity,
+  useUpdateActivity,
 } from '../actions/activity-actions.js';
 import { connectionSelector } from '../selectors/keyserver-selectors.js';
 import { getMostRecentNonLocalMessageID } from '../shared/message-utils.js';
 import { threadIsPending } from '../shared/thread-utils.js';
 import { queueActivityUpdatesActionType } from '../types/activity-types.js';
-import {
-  useServerCall,
-  useDispatchActionPromise,
-} from '../utils/action-utils.js';
+import { useDispatchActionPromise } from '../utils/action-utils.js';
 import { useSelector } from '../utils/redux-utils.js';
 
 type Props = {
@@ -62,7 +59,7 @@
 
   const dispatch = useDispatch();
   const dispatchActionPromise = useDispatchActionPromise();
-  const callUpdateActivity = useServerCall(updateActivity);
+  const callUpdateActivity = useUpdateActivity();
 
   React.useEffect(() => {
     const activityUpdates = [];
@@ -125,7 +122,7 @@
     }
     dispatchActionPromise(
       updateActivityActionTypes,
-      callUpdateActivity(activityUpdates),
+      callUpdateActivity({ activityUpdates }),
     );
   });