diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -96,7 +96,6 @@
   ChangeThreadSettingsPayload,
   UserProfileThreadInfo,
   RelativeMemberInfo,
-  ThreadInfo,
   MixedRawThreadInfos,
 } from '../types/thread-types.js';
 import { updateTypes } from '../types/update-types-enum.js';
@@ -127,7 +126,12 @@
 import { pendingThreadIDRegex } from '../utils/validation-utils.js';
 
 function threadHasPermission(
-  threadInfo: ?(ThreadInfo | LegacyRawThreadInfo | RawThreadInfo),
+  threadInfo: ?(
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+  ),
   permission: ThreadPermission,
 ): boolean {
   if (!threadInfo) {
@@ -145,7 +149,12 @@
 }
 
 function viewerIsMember(
-  threadInfo: ?(LegacyRawThreadInfo | RawThreadInfo | ThreadInfo),
+  threadInfo: ?(
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+  ),
 ): boolean {
   return !!(
     threadInfo &&
@@ -154,13 +163,20 @@
   );
 }
 
-function threadIsInHome(threadInfo: ?(RawThreadInfo | ThreadInfo)): boolean {
+function threadIsInHome(
+  threadInfo: ?(RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo),
+): boolean {
   return !!(threadInfo && threadInfo.currentUser.subscription.home);
 }
 
 // Can have messages
 function threadInChatList(
-  threadInfo: ?(LegacyRawThreadInfo | RawThreadInfo | ThreadInfo),
+  threadInfo: ?(
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return (
     viewerIsMember(threadInfo) &&
@@ -168,26 +184,32 @@
   );
 }
 
-function threadIsTopLevel(threadInfo: ?(RawThreadInfo | ThreadInfo)): boolean {
+function threadIsTopLevel(
+  threadInfo: ?(RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo),
+): boolean {
   return threadInChatList(threadInfo) && threadIsChannel(threadInfo);
 }
 
-function threadIsChannel(threadInfo: ?(RawThreadInfo | ThreadInfo)): boolean {
+function threadIsChannel(
+  threadInfo: ?(RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo),
+): boolean {
   return !!(threadInfo && threadInfo.type !== threadTypes.SIDEBAR);
 }
 
-function threadIsSidebar(threadInfo: ?(RawThreadInfo | ThreadInfo)): boolean {
+function threadIsSidebar(
+  threadInfo: ?(RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo),
+): boolean {
   return threadInfo?.type === threadTypes.SIDEBAR;
 }
 
 function threadInBackgroundChatList(
-  threadInfo: ?(RawThreadInfo | ThreadInfo),
+  threadInfo: ?(RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo),
 ): boolean {
   return threadInChatList(threadInfo) && !threadIsInHome(threadInfo);
 }
 
 function threadInHomeChatList(
-  threadInfo: ?(RawThreadInfo | ThreadInfo),
+  threadInfo: ?(RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo),
 ): boolean {
   return threadInChatList(threadInfo) && threadIsInHome(threadInfo);
 }
@@ -195,7 +217,12 @@
 // Can have Calendar entries,
 // does appear as a top-level entity in the thread list
 function threadInFilterList(
-  threadInfo: ?(LegacyRawThreadInfo | RawThreadInfo | ThreadInfo),
+  threadInfo: ?(
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
 ): boolean {
   return (
     threadInChatList(threadInfo) &&
@@ -205,7 +232,12 @@
 }
 
 function userIsMember(
-  threadInfo: ?(LegacyRawThreadInfo | RawThreadInfo | ThreadInfo),
+  threadInfo: ?(
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo
+  ),
   userID: string,
 ): boolean {
   if (!threadInfo) {
@@ -235,7 +267,11 @@
 }
 
 function threadMembersWithoutAddedAshoat<
-  T: LegacyRawThreadInfo | RawThreadInfo | ThreadInfo,
+  T:
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
 >(threadInfo: T): $PropertyType<T, 'members'> {
   if (threadInfo.community !== genesis.id) {
     return threadInfo.members;
@@ -245,12 +281,18 @@
   );
 }
 
-function threadIsGroupChat(threadInfo: ThreadInfo): boolean {
+function threadIsGroupChat(
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
+): boolean {
   return threadInfo.members.length > 2;
 }
 
 function threadOrParentThreadIsGroupChat(
-  threadInfo: LegacyRawThreadInfo | RawThreadInfo | ThreadInfo,
+  threadInfo:
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
 ) {
   return threadMembersWithoutAddedAshoat(threadInfo).length > 2;
 }
@@ -264,7 +306,11 @@
 }
 
 function getSingleOtherUser(
-  threadInfo: LegacyRawThreadInfo | RawThreadInfo | ThreadInfo,
+  threadInfo:
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
   viewerID: ?string,
 ): ?string {
   if (!viewerID) {
@@ -326,7 +372,7 @@
   +viewerID: string,
   +threadType: ThreadType,
   +members: $ReadOnlyArray<UserIDAndUsername>,
-  +parentThreadInfo?: ?ThreadInfo,
+  +parentThreadInfo?: ?(LegacyThreadInfo | MinimallyEncodedThreadInfo),
   +threadColor?: ?string,
   +name?: ?string,
   +sourceMessageID?: string,
@@ -411,7 +457,7 @@
 }
 
 type PendingPersonalThread = {
-  +threadInfo: ThreadInfo,
+  +threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   +pendingPersonalThreadUserInfo: UserInfo,
 };
 
@@ -471,7 +517,7 @@
 // Returns map from user ID to AccountUserInfo
 function extractMentionedMembers(
   text: string,
-  threadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
 ): Map<string, AccountUserInfo> {
   const memberMap = memberLowercaseUsernameMap(threadInfo.members);
   const mentions = extractUserMentionsFromText(text);
@@ -490,8 +536,8 @@
 // they will be automatically added to that sidebar
 function extractNewMentionedParentMembers(
   messageText: string,
-  threadInfo: ThreadInfo,
-  parentThreadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
+  parentThreadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
 ): AccountUserInfo[] {
   const mentionedMembersOfParent = extractMentionedMembers(
     messageText,
@@ -507,7 +553,7 @@
 
 type SharedCreatePendingSidebarInput = {
   +sourceMessageInfo: ComposableMessageInfo | RobotextMessageInfo,
-  +parentThreadInfo: ThreadInfo,
+  +parentThreadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   +loggedInUserInfo: LoggedInUserInfo,
 };
 
@@ -679,7 +725,7 @@
 }
 
 type CreateRealThreadParameters = {
-  +threadInfo: ThreadInfo,
+  +threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   +dispatchActionPromise: DispatchActionPromise,
   +createNewThread: ClientNewThreadRequest => Promise<NewThreadResult>,
   +sourceMessageID: ?string,
@@ -868,7 +914,9 @@
     : rawThreadInfo;
 }
 
-function threadUIName(threadInfo: ThreadInfo): string | ThreadEntity {
+function threadUIName(
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
+): string | ThreadEntity {
   if (threadInfo.name) {
     return firstLine(threadInfo.name);
   }
@@ -902,7 +950,7 @@
   viewerID: ?string,
   userInfos: UserInfos,
 ): MinimallyEncodedThreadInfo {
-  let threadInfo: ThreadInfo;
+  let threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo;
   if (rawThreadInfo.minimallyEncoded) {
     threadInfo = {
       minimallyEncoded: true,
@@ -1013,7 +1061,11 @@
 }
 
 function threadIsWithBlockedUserOnly(
-  threadInfo: LegacyRawThreadInfo | RawThreadInfo | ThreadInfo,
+  threadInfo:
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
   checkOnlyViewerBlock?: boolean,
@@ -1045,7 +1097,11 @@
 }
 
 function threadFrozenDueToBlock(
-  threadInfo: LegacyRawThreadInfo | RawThreadInfo | ThreadInfo,
+  threadInfo:
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
@@ -1053,7 +1109,7 @@
 }
 
 function threadFrozenDueToViewerBlock(
-  threadInfo: RawThreadInfo | ThreadInfo,
+  threadInfo: RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
@@ -1069,7 +1125,7 @@
 
 function memberIsAdmin(
   memberInfo: RelativeMemberInfo | MemberInfo,
-  threadInfo: RawThreadInfo | ThreadInfo,
+  threadInfo: RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo,
 ): boolean {
   return !!(
     memberInfo.role && roleIsAdminRole(threadInfo.roles[memberInfo.role])
@@ -1095,7 +1151,8 @@
   threadInfo: ?(
     | LegacyRawThreadInfo
     | RawThreadInfo
-    | ThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo
     | ServerThreadInfo
   ),
 ): boolean {
@@ -1106,7 +1163,11 @@
 }
 
 function threadOrParentThreadHasAdminRole(
-  threadInfo: LegacyRawThreadInfo | RawThreadInfo | ThreadInfo,
+  threadInfo:
+    | LegacyRawThreadInfo
+    | RawThreadInfo
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
 ) {
   return (
     threadMembersWithoutAddedAshoat(threadInfo).filter(member =>
@@ -1207,7 +1268,9 @@
   }
 }
 
-function useWatchThread(threadInfo: ?ThreadInfo) {
+function useWatchThread(
+  threadInfo: ?(LegacyThreadInfo | MinimallyEncodedThreadInfo),
+) {
   const dispatchActionPromise = useDispatchActionPromise();
   const callFetchMostRecentMessages = useFetchMostRecentMessages();
 
@@ -1240,10 +1303,10 @@
 };
 type ExistingThreadInfoFinder = (
   params: ExistingThreadInfoFinderParams,
-) => ?ThreadInfo;
+) => ?(LegacyThreadInfo | MinimallyEncodedThreadInfo);
 // TODO (atul): Parameterize function once `createPendingThread` is updated.
 function useExistingThreadInfoFinder(
-  baseThreadInfo: ?ThreadInfo,
+  baseThreadInfo: ?(LegacyThreadInfo | MinimallyEncodedThreadInfo),
 ): ExistingThreadInfoFinder {
   const threadInfos = useSelector(threadInfoSelector);
   const loggedInUserInfo = useLoggedInUserInfo();
@@ -1253,7 +1316,9 @@
     pendingToRealizedThreadIDsSelector(state.threadStore.threadInfos),
   );
   return React.useCallback(
-    (params: ExistingThreadInfoFinderParams): ?ThreadInfo => {
+    (
+      params: ExistingThreadInfoFinderParams,
+    ): ?(LegacyThreadInfo | MinimallyEncodedThreadInfo) => {
       if (!baseThreadInfo) {
         return null;
       }
@@ -1358,7 +1423,8 @@
     | ServerThreadInfo
     | LegacyRawThreadInfo
     | RawThreadInfo
-    | ThreadInfo,
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
   memberID: string,
   permission: ThreadPermission,
 ): boolean {
@@ -1375,7 +1441,7 @@
 }
 
 function useCanCreateSidebarFromMessage(
-  threadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   messageInfo: ComposableMessageInfo | RobotextMessageInfo,
 ): boolean {
   const messageCreatorUserInfo = useSelector(
@@ -1404,7 +1470,7 @@
 }
 
 function useSidebarExistsOrCanBeCreated(
-  threadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   messageItem: ChatMessageInfoItem,
 ): boolean {
   const canCreateSidebarFromMessage = useCanCreateSidebarFromMessage(
@@ -1414,7 +1480,9 @@
   return !!messageItem.threadCreatedFromMessage || canCreateSidebarFromMessage;
 }
 
-function checkIfDefaultMembersAreVoiced(threadInfo: ThreadInfo): boolean {
+function checkIfDefaultMembersAreVoiced(
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
+): boolean {
   const defaultRoleID = Object.keys(threadInfo.roles).find(
     roleID => threadInfo.roles[roleID].isDefault,
   );
@@ -1441,7 +1509,8 @@
     | ?ServerThreadInfo
     | LegacyRawThreadInfo
     | RawThreadInfo
-    | ThreadInfo,
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
   threadType: ThreadType,
 ): ?string {
   if (!parentThreadInfo) {
@@ -1461,7 +1530,8 @@
     | ?ServerThreadInfo
     | LegacyRawThreadInfo
     | RawThreadInfo
-    | ThreadInfo,
+    | LegacyThreadInfo
+    | MinimallyEncodedThreadInfo,
 ): ?string {
   if (!parentThreadInfo) {
     return null;
@@ -1479,7 +1549,7 @@
 function getThreadListSearchResults(
   chatListData: $ReadOnlyArray<ChatThreadItem>,
   searchText: string,
-  threadFilter: ThreadInfo => boolean,
+  threadFilter: (LegacyThreadInfo | MinimallyEncodedThreadInfo) => boolean,
   threadSearchResults: $ReadOnlySet<string>,
   usersSearchResults: $ReadOnlyArray<GlobalAccountUserInfo>,
   loggedInUserInfo: ?LoggedInUserInfo,
@@ -1567,7 +1637,7 @@
 }
 
 function removeMemberFromThread(
-  threadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   memberInfo: RelativeMemberInfo,
   dispatchActionPromise: DispatchActionPromise,
   removeUserFromThreadServerCall: (
@@ -1587,7 +1657,7 @@
 
 function getAvailableThreadMemberActions(
   memberInfo: RelativeMemberInfo,
-  threadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   canEdit: ?boolean = true,
 ): $ReadOnlyArray<'change_role' | 'remove_user'> {
   const role = memberInfo.role;
@@ -1622,11 +1692,11 @@
 }
 
 function patchThreadInfoToIncludeMentionedMembersOfParent(
-  threadInfo: ThreadInfo,
-  parentThreadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
+  parentThreadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
   messageText: string,
   viewerID: string,
-): ThreadInfo {
+): LegacyThreadInfo | MinimallyEncodedThreadInfo {
   const members: UserIDAndUsername[] = threadInfo.members
     .map(({ id, username }) =>
       username ? ({ id, username }: UserIDAndUsername) : null,
@@ -1653,7 +1723,7 @@
 }
 
 function threadInfoInsideCommunity(
-  threadInfo: RawThreadInfo | ThreadInfo,
+  threadInfo: RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo,
   communityID: string,
 ): boolean {
   return threadInfo.community === communityID || threadInfo.id === communityID;
@@ -1664,7 +1734,7 @@
 };
 
 function useRoleMemberCountsForCommunity(
-  threadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
 ): RoleAndMemberCount {
   return React.useMemo(() => {
     const roleIDsToNames: { [string]: string } = {};
@@ -1701,7 +1771,7 @@
 // the set of permission literals for each role to user-facing permission enums
 // to help pre-populate the permission checkboxes when editing roles.
 function useRoleUserSurfacedPermissions(
-  threadInfo: ThreadInfo,
+  threadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
 ): RoleUserSurfacedPermissions {
   return React.useMemo(() => {
     const roleNamesToPermissions: { [string]: Set<UserSurfacedPermission> } =
@@ -1735,14 +1805,16 @@
   }, [threadInfo]);
 }
 
-function communityOrThreadNoun(threadInfo: RawThreadInfo | ThreadInfo): string {
+function communityOrThreadNoun(
+  threadInfo: RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo,
+): string {
   return threadTypeIsCommunityRoot(threadInfo.type)
     ? 'community'
     : threadNoun(threadInfo.type, threadInfo.parentThreadID);
 }
 
 function getThreadsToDeleteText(
-  threadInfo: RawThreadInfo | ThreadInfo,
+  threadInfo: RawThreadInfo | LegacyThreadInfo | MinimallyEncodedThreadInfo,
 ): string {
   return `${
     threadTypeIsCommunityRoot(threadInfo.type)
@@ -1777,13 +1849,19 @@
     }
 
     if (isViewerProfile) {
-      const privateThreadInfo: ?ThreadInfo = privateThreadInfos[0];
+      const privateThreadInfo: ?(
+        | LegacyThreadInfo
+        | MinimallyEncodedThreadInfo
+      ) = privateThreadInfos[0];
 
       return privateThreadInfo ? { threadInfo: privateThreadInfo } : null;
     }
 
     if (usersWithPersonalThread.has(userID)) {
-      const personalThreadInfo: ?ThreadInfo = personalThreadInfos.find(
+      const personalThreadInfo: ?(
+        | LegacyThreadInfo
+        | MinimallyEncodedThreadInfo
+      ) = personalThreadInfos.find(
         threadInfo =>
           userID === getSingleOtherUser(threadInfo, loggedInUserInfo.id),
       );