diff --git a/lib/actions/user-actions.js b/lib/actions/user-actions.js
--- a/lib/actions/user-actions.js
+++ b/lib/actions/user-actions.js
@@ -1004,6 +1004,8 @@
     return { updates };
   };
 
+const processNewUserIDsActionType = 'PROCESS_NEW_USER_IDS';
+
 export {
   changeKeyserverUserPasswordActionTypes,
   changeKeyserverUserPassword,
@@ -1049,4 +1051,5 @@
   useIdentityWalletRegister,
   identityGenerateNonceActionTypes,
   useIdentityGenerateNonce,
+  processNewUserIDsActionType,
 };
diff --git a/lib/reducers/user-reducer.js b/lib/reducers/user-reducer.js
--- a/lib/reducers/user-reducer.js
+++ b/lib/reducers/user-reducer.js
@@ -10,6 +10,7 @@
   newThreadActionTypes,
 } from '../actions/thread-actions.js';
 import {
+  processNewUserIDsActionType,
   identityLogInActionTypes,
   identityRegisterActionTypes,
   deleteAccountActionTypes,
@@ -200,7 +201,34 @@
   $ReadOnlyArray<ClientUserInconsistencyReportCreationRequest>,
   $ReadOnlyArray<UserStoreOperation>,
 ] {
-  if (
+  if (action.type === processNewUserIDsActionType) {
+    const filteredUserIDs = action.payload.userIDs.filter(
+      id => !state.userInfos[id],
+    );
+    const newUserInfosArray = filteredUserIDs.map(id => ({
+      id,
+      username: null,
+    }));
+    const newUserInfos: UserInfos = _keyBy(userInfo => userInfo.id)(
+      newUserInfosArray,
+    );
+
+    const userStoreOps: $ReadOnlyArray<UserStoreOperation> =
+      convertUserInfosToReplaceUserOps(newUserInfos);
+    const processedUserInfos: UserInfos = processUserStoreOps(
+      state.userInfos,
+      userStoreOps,
+    );
+
+    return [
+      {
+        ...state,
+        userInfos: processedUserInfos,
+      },
+      [],
+      userStoreOps,
+    ];
+  } else if (
     action.type === joinThreadActionTypes.success ||
     action.type === newThreadActionTypes.success
   ) {
diff --git a/lib/types/redux-types.js b/lib/types/redux-types.js
--- a/lib/types/redux-types.js
+++ b/lib/types/redux-types.js
@@ -1441,6 +1441,13 @@
         +error: true,
         +payload: Error,
         +loadingInfo: LoadingInfo,
+      }
+    | {
+        +type: 'PROCESS_NEW_USER_IDS',
+        +payload: {
+          +userIDs: $ReadOnlyArray<string>,
+        },
+        +loadingInfo: LoadingInfo,
       },
 }>;