diff --git a/lib/selectors/user-selectors.js b/lib/selectors/user-selectors.js
index 01d0e5d45..60302d1b3 100644
--- a/lib/selectors/user-selectors.js
+++ b/lib/selectors/user-selectors.js
@@ -1,276 +1,293 @@
 // @flow
 
 import _memoize from 'lodash/memoize.js';
 import { createSelector } from 'reselect';
 
 import bots from '../facts/bots.js';
 import {
   getAvatarForUser,
   getRandomDefaultEmojiAvatar,
 } from '../shared/avatar-utils.js';
 import { getSingleOtherUser } from '../shared/thread-utils.js';
 import {
   type AuxUserInfos,
   type AuxUserInfo,
 } from '../types/aux-user-types.js';
 import type { ClientEmojiAvatar } from '../types/avatar-types';
 import type {
   RelativeMemberInfo,
   RawThreadInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
 import type { BaseAppState } from '../types/redux-types.js';
 import { userRelationshipStatus } from '../types/relationship-types.js';
 import { threadTypes } from '../types/thread-types-enum.js';
 import type { RawThreadInfos } from '../types/thread-types.js';
 import type {
   UserInfos,
   RelativeUserInfo,
   AccountUserInfo,
   CurrentUserInfo,
 } from '../types/user-types.js';
 import { entries, values } from '../utils/objects.js';
 
 // Used for specific message payloads that include an array of user IDs, ie.
 // array of initial users, array of added users
 function userIDsToRelativeUserInfos(
   userIDs: $ReadOnlyArray<string>,
   viewerID: ?string,
   userInfos: UserInfos,
 ): RelativeUserInfo[] {
   const relativeUserInfos: RelativeUserInfo[] = [];
   for (const userID of userIDs) {
     const username = userInfos[userID] ? userInfos[userID].username : null;
     const relativeUserInfo = {
       id: userID,
       username,
       isViewer: userID === viewerID,
     };
     if (userID === viewerID) {
       relativeUserInfos.unshift(relativeUserInfo);
     } else {
       relativeUserInfos.push(relativeUserInfo);
     }
   }
   return relativeUserInfos;
 }
 
 function getRelativeMemberInfos(
   threadInfo: ?RawThreadInfo,
   currentUserID: ?string,
   userInfos: UserInfos,
 ): $ReadOnlyArray<RelativeMemberInfo> {
   const relativeMemberInfos: RelativeMemberInfo[] = [];
   if (!threadInfo) {
     return relativeMemberInfos;
   }
   const memberInfos = threadInfo.members;
   for (const memberInfo of memberInfos) {
     if (!memberInfo.role) {
       continue;
     }
     const username = userInfos[memberInfo.id]
       ? userInfos[memberInfo.id].username
       : null;
     const { id, role, isSender, minimallyEncoded } = memberInfo;
     if (memberInfo.id === currentUserID) {
       relativeMemberInfos.unshift({
         id,
         role,
         isSender,
         minimallyEncoded,
         username,
         isViewer: true,
       });
     } else {
       relativeMemberInfos.push({
         id,
         role,
         isSender,
         minimallyEncoded,
         username,
         isViewer: false,
       });
     }
   }
   return relativeMemberInfos;
 }
 
 const emptyArray: $ReadOnlyArray<RelativeMemberInfo> = [];
 
 // Includes current user at the start
 const baseRelativeMemberInfoSelectorForMembersOfThread: (
   threadID: ?string,
 ) => (state: BaseAppState<>) => $ReadOnlyArray<RelativeMemberInfo> = (
   threadID: ?string,
 ) => {
   if (!threadID) {
     return () => emptyArray;
   }
   return createSelector(
     (state: BaseAppState<>) => state.threadStore.threadInfos[threadID],
     (state: BaseAppState<>) =>
       state.currentUserInfo && state.currentUserInfo.id,
     (state: BaseAppState<>) => state.userStore.userInfos,
     getRelativeMemberInfos,
   );
 };
 
 const relativeMemberInfoSelectorForMembersOfThread: (
   threadID: ?string,
 ) => (state: BaseAppState<>) => $ReadOnlyArray<RelativeMemberInfo> = _memoize(
   baseRelativeMemberInfoSelectorForMembersOfThread,
 );
 
 const userInfoSelectorForPotentialMembers: (state: BaseAppState<>) => {
   [id: string]: AccountUserInfo,
 } = createSelector(
   (state: BaseAppState<>) => state.userStore.userInfos,
   (state: BaseAppState<>) => state.currentUserInfo && state.currentUserInfo.id,
   (
     userInfos: UserInfos,
     currentUserID: ?string,
   ): { [id: string]: AccountUserInfo } => {
     const availableUsers: { [id: string]: AccountUserInfo } = {};
 
     for (const id in userInfos) {
       const { username, relationshipStatus } = userInfos[id];
       if (id === currentUserID || !username) {
         continue;
       }
       if (
         relationshipStatus !== userRelationshipStatus.BLOCKED_VIEWER &&
         relationshipStatus !== userRelationshipStatus.BOTH_BLOCKED
       ) {
         availableUsers[id] = { id, username, relationshipStatus };
       }
     }
     return availableUsers;
   },
 );
 
 const isLoggedIn = (state: BaseAppState<>): boolean =>
   !!(
     state.currentUserInfo &&
     !state.currentUserInfo.anonymous &&
     state.dataLoaded
   );
 
 const isLoggedInToKeyserver: (
   keyserverID: ?string,
 ) => (state: BaseAppState<>) => boolean = _memoize(
   (keyserverID: ?string) => (state: BaseAppState<>) => {
     if (!keyserverID) {
       return false;
     }
     const cookie = state.keyserverStore.keyserverInfos[keyserverID]?.cookie;
     return !!cookie && cookie.startsWith('user=');
   },
 );
 
 const usersWithPersonalThreadSelector: (
   state: BaseAppState<>,
 ) => $ReadOnlySet<string> = createSelector(
   (state: BaseAppState<>) => state.currentUserInfo && state.currentUserInfo.id,
   (state: BaseAppState<>) => state.threadStore.threadInfos,
   (viewerID: ?string, threadInfos: RawThreadInfos) => {
     const personalThreadMembers = new Set<string>();
 
     for (const threadID in threadInfos) {
       const thread = threadInfos[threadID];
       if (
         thread.type !== threadTypes.GENESIS_PERSONAL ||
         !thread.members.find(member => member.id === viewerID)
       ) {
         continue;
       }
       const otherMemberID = getSingleOtherUser(thread, viewerID);
       if (otherMemberID) {
         personalThreadMembers.add(otherMemberID);
       }
     }
     return personalThreadMembers;
   },
 );
 
 const savedEmojiAvatarSelectorForCurrentUser: (
   state: BaseAppState<>,
 ) => () => ClientEmojiAvatar = createSelector(
   (state: BaseAppState<>) => state.currentUserInfo && state.currentUserInfo,
   (currentUser: ?CurrentUserInfo) => {
     return () => {
       let userAvatar = getAvatarForUser(currentUser);
       if (userAvatar.type !== 'emoji') {
         userAvatar = getRandomDefaultEmojiAvatar();
       }
       return userAvatar;
     };
   },
 );
 
 const getRelativeUserIDs: (state: BaseAppState<>) => $ReadOnlyArray<string> =
   createSelector(
     (state: BaseAppState<>) => state.userStore.userInfos,
     (userInfos: UserInfos): $ReadOnlyArray<string> => Object.keys(userInfos),
   );
 
 const usersWithMissingDeviceListSelector: (
   state: BaseAppState<>,
 ) => $ReadOnlyArray<string> = createSelector(
   getRelativeUserIDs,
   (state: BaseAppState<>) => state.auxUserStore.auxUserInfos,
   (
     userIDs: $ReadOnlyArray<string>,
     auxUserInfos: AuxUserInfos,
   ): $ReadOnlyArray<string> =>
     userIDs.filter(
       userID =>
         (!auxUserInfos[userID] || !auxUserInfos[userID].deviceList) &&
         userID !== bots.commbot.userID,
     ),
 );
 
 // Foreign Peer Devices are all devices of users we are aware of,
 // but not our own devices.
 const getForeignPeerDevices: (state: BaseAppState<>) => $ReadOnlyArray<string> =
   createSelector(
     (state: BaseAppState<>) => state.auxUserStore.auxUserInfos,
     (state: BaseAppState<>) =>
       state.currentUserInfo && state.currentUserInfo.id,
     (
       auxUserInfos: AuxUserInfos,
       currentUserID: ?string,
     ): $ReadOnlyArray<string> =>
       entries(auxUserInfos)
         .map(([userID, auxUserInfo]: [string, AuxUserInfo]) =>
           userID !== currentUserID && auxUserInfo.deviceList?.devices
             ? auxUserInfo.deviceList.devices
             : [],
         )
         .flat(),
   );
 
 const getAllPeerDevices: (state: BaseAppState<>) => $ReadOnlyArray<string> =
   createSelector(
     (state: BaseAppState<>) => state.auxUserStore.auxUserInfos,
     (auxUserInfos: AuxUserInfos): $ReadOnlyArray<string> =>
       values(auxUserInfos)
         .map(
           (auxUserInfo: AuxUserInfo) => auxUserInfo.deviceList?.devices ?? [],
         )
         .flat(),
   );
 
+const getAllPeerUserIDAndDeviceIDs: (
+  state: BaseAppState<>,
+) => $ReadOnlyArray<{ +userID: string, +deviceID: string }> = createSelector(
+  (state: BaseAppState<>) => state.auxUserStore.auxUserInfos,
+  (
+    auxUserInfos: AuxUserInfos,
+  ): $ReadOnlyArray<{ +userID: string, +deviceID: string }> =>
+    entries(auxUserInfos).flatMap(
+      ([userID, { deviceList }]: [string, AuxUserInfo]) =>
+        deviceList?.devices.map(deviceID => ({
+          userID,
+          deviceID,
+        })) ?? [],
+    ),
+);
+
 export {
   userIDsToRelativeUserInfos,
   getRelativeMemberInfos,
   relativeMemberInfoSelectorForMembersOfThread,
   userInfoSelectorForPotentialMembers,
   isLoggedIn,
   isLoggedInToKeyserver,
   usersWithPersonalThreadSelector,
   savedEmojiAvatarSelectorForCurrentUser,
   getRelativeUserIDs,
   usersWithMissingDeviceListSelector,
   getForeignPeerDevices,
   getAllPeerDevices,
+  getAllPeerUserIDAndDeviceIDs,
 };