diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -283,7 +283,7 @@
   +startsCluster: boolean,
   endsCluster: boolean,
   +robotext: EntityText,
-  +threadCreatedFromMessage: ?LegacyThreadInfo | ?ThreadInfo,
+  +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
 };
 export type ChatMessageInfoItem =
@@ -296,7 +296,7 @@
       +startsConversation: boolean,
       +startsCluster: boolean,
       endsCluster: boolean,
-      +threadCreatedFromMessage: ?LegacyThreadInfo | ?ThreadInfo,
+      +threadCreatedFromMessage: ?ThreadInfo,
       +reactions: ReactionInfo,
       +hasBeenEdited: boolean,
       +isPinned: boolean,
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
@@ -1824,18 +1824,16 @@
     }
 
     if (isViewerProfile) {
-      const privateThreadInfo: ?(LegacyThreadInfo | ThreadInfo) =
-        privateThreadInfos[0];
+      const privateThreadInfo: ?ThreadInfo = privateThreadInfos[0];
 
       return privateThreadInfo ? { threadInfo: privateThreadInfo } : null;
     }
 
     if (usersWithPersonalThread.has(userID)) {
-      const personalThreadInfo: ?(LegacyThreadInfo | ThreadInfo) =
-        personalThreadInfos.find(
-          threadInfo =>
-            userID === getSingleOtherUser(threadInfo, loggedInUserInfo.id),
-        );
+      const personalThreadInfo: ?ThreadInfo = personalThreadInfos.find(
+        threadInfo =>
+          userID === getSingleOtherUser(threadInfo, loggedInUserInfo.id),
+      );
 
       return personalThreadInfo ? { threadInfo: personalThreadInfo } : null;
     }
diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -498,6 +498,6 @@
 };
 
 export type UserProfileThreadInfo = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +pendingPersonalThreadUserInfo?: UserInfo,
 };
diff --git a/native/calendar/calendar.react.js b/native/calendar/calendar.react.js
--- a/native/calendar/calendar.react.js
+++ b/native/calendar/calendar.react.js
@@ -37,7 +37,6 @@
 import type { LoadingStatus } from 'lib/types/loading-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import type { ConnectionStatus } from 'lib/types/socket-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import {
   dateFromString,
   dateString,
@@ -115,7 +114,7 @@
   | {
       itemType: 'entryInfo',
       entryInfo: EntryInfoWithHeight,
-      threadInfo: LegacyThreadInfo | ThreadInfo,
+      threadInfo: ThreadInfo,
     };
 type ExtraData = {
   +activeEntries: { +[key: string]: boolean },
diff --git a/native/calendar/entry.react.js b/native/calendar/entry.react.js
--- a/native/calendar/entry.react.js
+++ b/native/calendar/entry.react.js
@@ -48,10 +48,6 @@
 } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import type { Dispatch } from 'lib/types/redux-types.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
-import type {
-  LegacyResolvedThreadInfo,
-  LegacyThreadInfo,
-} from 'lib/types/thread-types.js';
 import { dateString } from 'lib/utils/date-utils.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
 import { ServerError } from 'lib/utils/errors.js';
@@ -194,11 +190,11 @@
 };
 type BaseProps = {
   ...SharedProps,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 type Props = {
   ...SharedProps,
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   // Redux state
   +calendarQuery: () => CalendarQuery,
   +online: boolean,
diff --git a/native/chat/chat-context-provider.react.js b/native/chat/chat-context-provider.react.js
--- a/native/chat/chat-context-provider.react.js
+++ b/native/chat/chat-context-provider.react.js
@@ -3,7 +3,6 @@
 import * as React from 'react';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import type { SidebarAnimationType } from './chat-context.js';
 import { ChatContext } from './chat-context.js';
@@ -17,7 +16,7 @@
 
 export type MeasurementTask = {
   +messages: $ReadOnlyArray<NativeChatMessageItem>,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +onMessagesMeasured: (
     messagesWithHeight: $ReadOnlyArray<ChatMessageItemWithHeight>,
     measuredHeights: $ReadOnlyMap<string, number>,
@@ -38,7 +37,7 @@
   const measureMessages = React.useCallback(
     (
       messages: ?$ReadOnlyArray<NativeChatMessageItem>,
-      threadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+      threadInfo: ?ThreadInfo,
       onMessagesMeasured: ($ReadOnlyArray<ChatMessageItemWithHeight>) => mixed,
       measurerID: number,
     ) => {
@@ -94,7 +93,7 @@
     return {
       measure: (
         messages: ?$ReadOnlyArray<NativeChatMessageItem>,
-        threadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+        threadInfo: ?ThreadInfo,
         onMessagesMeasured: (
           $ReadOnlyArray<ChatMessageItemWithHeight>,
         ) => mixed,
diff --git a/native/chat/chat-context.js b/native/chat/chat-context.js
--- a/native/chat/chat-context.js
+++ b/native/chat/chat-context.js
@@ -5,14 +5,13 @@
 
 import type { SetState } from 'lib/types/hook-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import type { NativeChatMessageItem } from './message-data.react.js';
 import type { ChatMessageItemWithHeight } from '../types/chat-types.js';
 
 export type MessagesMeasurer = (
   ?$ReadOnlyArray<NativeChatMessageItem>,
-  ?LegacyThreadInfo | ?ThreadInfo,
+  ?ThreadInfo,
   ($ReadOnlyArray<ChatMessageItemWithHeight>) => mixed,
 ) => void;
 
diff --git a/native/chat/chat-input-bar.react.js b/native/chat/chat-input-bar.react.js
--- a/native/chat/chat-input-bar.react.js
+++ b/native/chat/chat-input-bar.react.js
@@ -79,7 +79,6 @@
 import type {
   ChatMentionCandidates,
   ClientThreadJoinRequest,
-  LegacyThreadInfo,
   RelativeMemberInfo,
   ThreadJoinPayload,
 } from 'lib/types/thread-types.js';
@@ -274,7 +273,7 @@
 };
 
 type BaseProps = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 type Props = {
   ...BaseProps,
@@ -298,7 +297,7 @@
   +userMentionsCandidates: $ReadOnlyArray<RelativeMemberInfo>,
   +chatMentionSearchIndex: SentencePrefixSearchIndex,
   +chatMentionCandidates: ChatMentionCandidates,
-  +parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+  +parentThreadInfo: ?ThreadInfo,
   +editedMessagePreview: ?MessagePreviewResult,
   +editedMessageInfo: ?MessageInfo,
   +editMessage: (
diff --git a/native/chat/chat-router.js b/native/chat/chat-router.js
--- a/native/chat/chat-router.js
+++ b/native/chat/chat-router.js
@@ -12,7 +12,6 @@
 import { CommonActions, StackRouter } from '@react-navigation/native';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import { createNavigateToThreadAction } from './message-list-types.js';
 import {
@@ -40,7 +39,7 @@
 type ReplaceWithThreadAction = {
   +type: 'REPLACE_WITH_THREAD',
   +payload: {
-    +threadInfo: LegacyThreadInfo | ThreadInfo,
+    +threadInfo: ThreadInfo,
   },
 };
 type ClearThreadsAction = {
@@ -52,7 +51,7 @@
 type PushNewThreadAction = {
   +type: 'PUSH_NEW_THREAD',
   +payload: {
-    +threadInfo: LegacyThreadInfo | ThreadInfo,
+    +threadInfo: ThreadInfo,
   },
 };
 export type ChatRouterNavigationAction =
@@ -64,9 +63,9 @@
 
 export type ChatRouterNavigationHelpers = {
   +clearScreens: (routeNames: $ReadOnlyArray<string>) => void,
-  +replaceWithThread: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
+  +replaceWithThread: (threadInfo: ThreadInfo) => void,
   +clearThreads: (threadIDs: $ReadOnlyArray<string>) => void,
-  +pushNewThread: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
+  +pushNewThread: (threadInfo: ThreadInfo) => void,
 };
 
 function ChatRouter(
@@ -160,7 +159,7 @@
           routeNames,
         },
       }),
-      replaceWithThread: (threadInfo: LegacyThreadInfo | ThreadInfo) =>
+      replaceWithThread: (threadInfo: ThreadInfo) =>
         ({
           type: replaceWithThreadActionType,
           payload: { threadInfo },
@@ -169,7 +168,7 @@
         type: clearThreadsActionType,
         payload: { threadIDs },
       }),
-      pushNewThread: (threadInfo: LegacyThreadInfo | ThreadInfo) =>
+      pushNewThread: (threadInfo: ThreadInfo) =>
         ({
           type: pushNewThreadActionType,
           payload: { threadInfo },
diff --git a/native/chat/chat-thread-list-item.react.js b/native/chat/chat-thread-list-item.react.js
--- a/native/chat/chat-thread-list-item.react.js
+++ b/native/chat/chat-thread-list-item.react.js
@@ -5,7 +5,6 @@
 
 import type { ChatThreadItem } from 'lib/selectors/chat-selectors.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import type { UserInfo } from 'lib/types/user-types.js';
 import { shortAbsoluteDate } from 'lib/utils/date-utils.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
@@ -24,11 +23,11 @@
 type Props = {
   +data: ChatThreadItem,
   +onPressItem: (
-    threadInfo: LegacyThreadInfo | ThreadInfo,
+    threadInfo: ThreadInfo,
     pendingPersonalThreadUserInfo?: UserInfo,
   ) => void,
-  +onPressSeeMoreSidebars: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
-  +onSwipeableWillOpen: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
+  +onPressSeeMoreSidebars: (threadInfo: ThreadInfo) => void,
+  +onSwipeableWillOpen: (threadInfo: ThreadInfo) => void,
   +currentlyOpenedSwipeableId: string,
 };
 function ChatThreadListItem({
diff --git a/native/chat/chat-thread-list-see-more-sidebars.react.js b/native/chat/chat-thread-list-see-more-sidebars.react.js
--- a/native/chat/chat-thread-list-see-more-sidebars.react.js
+++ b/native/chat/chat-thread-list-see-more-sidebars.react.js
@@ -5,16 +5,15 @@
 import { Text } from 'react-native';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import { sidebarHeight } from './sidebar-item.react.js';
 import Button from '../components/button.react.js';
 import { useColors, useStyles } from '../themes/colors.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +unread: boolean,
-  +onPress: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
+  +onPress: (threadInfo: ThreadInfo) => void,
 };
 function ChatThreadListSeeMoreSidebars(props: Props): React.Node {
   const { onPress, threadInfo, unread } = props;
diff --git a/native/chat/chat-thread-list-sidebar.react.js b/native/chat/chat-thread-list-sidebar.react.js
--- a/native/chat/chat-thread-list-sidebar.react.js
+++ b/native/chat/chat-thread-list-sidebar.react.js
@@ -4,7 +4,7 @@
 import { View } from 'react-native';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo, SidebarInfo } from 'lib/types/thread-types.js';
+import type { SidebarInfo } from 'lib/types/thread-types.js';
 
 import { sidebarHeight, SidebarItem } from './sidebar-item.react.js';
 import SwipeableThread from './swipeable-thread.react.js';
@@ -16,8 +16,8 @@
 
 type Props = {
   +sidebarInfo: SidebarInfo,
-  +onPressItem: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
-  +onSwipeableWillOpen: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
+  +onPressItem: (threadInfo: ThreadInfo) => void,
+  +onSwipeableWillOpen: (threadInfo: ThreadInfo) => void,
   +currentlyOpenedSwipeableId: string,
   +extendArrow: boolean,
 };
diff --git a/native/chat/chat-thread-list.react.js b/native/chat/chat-thread-list.react.js
--- a/native/chat/chat-thread-list.react.js
+++ b/native/chat/chat-thread-list.react.js
@@ -177,10 +177,7 @@
   const searchInputRef = React.useRef<?React.ElementRef<typeof TextInput>>();
 
   const onPressItem = React.useCallback(
-    (
-      threadInfo: LegacyThreadInfo | ThreadInfo,
-      pendingPersonalThreadUserInfo?: UserInfo,
-    ) => {
+    (threadInfo: ThreadInfo, pendingPersonalThreadUserInfo?: UserInfo) => {
       onChangeSearchText('');
       if (searchInputRef.current) {
         searchInputRef.current.blur();
diff --git a/native/chat/compose-subchannel.react.js b/native/chat/compose-subchannel.react.js
--- a/native/chat/compose-subchannel.react.js
+++ b/native/chat/compose-subchannel.react.js
@@ -18,7 +18,6 @@
 import { threadInFilterList, userIsMember } from 'lib/shared/thread-utils.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import { type ThreadType, threadTypes } from 'lib/types/thread-types-enum.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { type AccountUserInfo } from 'lib/types/user-types.js';
 import { useDispatchActionPromise } from 'lib/utils/redux-promise-utils.js';
 
@@ -50,7 +49,7 @@
 
 export type ComposeSubchannelParams = {
   +threadType: ThreadType,
-  +parentThreadInfo: LegacyThreadInfo | ThreadInfo,
+  +parentThreadInfo: ThreadInfo,
 };
 
 type Props = {
@@ -205,29 +204,25 @@
     threadType,
   });
 
-  const existingThreads: $ReadOnlyArray<LegacyThreadInfo | ThreadInfo> =
-    React.useMemo(() => {
-      if (userInfoInputIDs.length === 0) {
-        return [];
-      }
-      return _flow(
-        _filter(
-          (threadInfo: LegacyThreadInfo | ThreadInfo) =>
-            threadInFilterList(threadInfo) &&
-            threadInfo.parentThreadID === parentThreadInfo.id &&
-            userInfoInputIDs.every(userID => userIsMember(threadInfo, userID)),
-        ),
-        _sortBy(
-          ([
-            'members.length',
-            (threadInfo: LegacyThreadInfo | ThreadInfo) =>
-              threadInfo.name ? 1 : 0,
-          ]: $ReadOnlyArray<
-            string | ((threadInfo: LegacyThreadInfo | ThreadInfo) => mixed),
-          >),
-        ),
-      )(threadInfos);
-    }, [userInfoInputIDs, threadInfos, parentThreadInfo]);
+  const existingThreads: $ReadOnlyArray<ThreadInfo> = React.useMemo(() => {
+    if (userInfoInputIDs.length === 0) {
+      return [];
+    }
+    return _flow(
+      _filter(
+        (threadInfo: ThreadInfo) =>
+          threadInFilterList(threadInfo) &&
+          threadInfo.parentThreadID === parentThreadInfo.id &&
+          userInfoInputIDs.every(userID => userIsMember(threadInfo, userID)),
+      ),
+      _sortBy(
+        ([
+          'members.length',
+          (threadInfo: ThreadInfo) => (threadInfo.name ? 1 : 0),
+        ]: $ReadOnlyArray<string | ((threadInfo: ThreadInfo) => mixed)>),
+      ),
+    )(threadInfos);
+  }, [userInfoInputIDs, threadInfos, parentThreadInfo]);
 
   const navigateToThread = useNavigateToThread();
   const onSelectExistingThread = React.useCallback(
diff --git a/native/chat/failed-send.react.js b/native/chat/failed-send.react.js
--- a/native/chat/failed-send.react.js
+++ b/native/chat/failed-send.react.js
@@ -10,7 +10,6 @@
 import type { RawComposableMessageInfo } from 'lib/types/message-types.js';
 import { assertComposableRawMessage } from 'lib/types/message-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import { multimediaMessageSendFailed } from './multimedia-message-utils.js';
 import textMessageSendFailed from './text-message-send-failed.js';
@@ -47,7 +46,7 @@
   +rawMessageInfo: ?RawComposableMessageInfo,
   +styles: $ReadOnly<typeof unboundStyles>,
   +inputState: ?InputState,
-  +parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+  +parentThreadInfo: ?ThreadInfo,
 };
 class FailedSend extends React.PureComponent<Props> {
   retryingText = false;
diff --git a/native/chat/image-paste-modal.react.js b/native/chat/image-paste-modal.react.js
--- a/native/chat/image-paste-modal.react.js
+++ b/native/chat/image-paste-modal.react.js
@@ -7,7 +7,6 @@
 
 import type { PhotoPaste } from 'lib/types/media-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import sleep from 'lib/utils/sleep.js';
 
 import Modal from '../components/modal.react.js';
@@ -18,7 +17,7 @@
 
 export type ImagePasteModalParams = {
   +imagePasteStagingInfo: PhotoPaste,
-  +thread: LegacyThreadInfo | ThreadInfo,
+  +thread: ThreadInfo,
 };
 
 const safeAreaEdges = ['top'];
diff --git a/native/chat/inline-engagement.react.js b/native/chat/inline-engagement.react.js
--- a/native/chat/inline-engagement.react.js
+++ b/native/chat/inline-engagement.react.js
@@ -129,8 +129,8 @@
 
 type Props = {
   +messageInfo: MessageInfo,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
-  +sidebarThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+  +threadInfo: ThreadInfo,
+  +sidebarThreadInfo: ?ThreadInfo,
   +reactions: ReactionInfo,
   +disabled?: boolean,
   +positioning?: 'left' | 'right' | 'center',
diff --git a/native/chat/message-list-container.react.js b/native/chat/message-list-container.react.js
--- a/native/chat/message-list-container.react.js
+++ b/native/chat/message-list-container.react.js
@@ -18,7 +18,6 @@
   useExistingThreadInfoFinder,
 } from 'lib/shared/thread-utils.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import type { AccountUserInfo, UserListItem } from 'lib/types/user-types.js';
 import { pinnedMessageCountText } from 'lib/utils/message-pinning-utils.js';
 
@@ -87,8 +86,8 @@
   +updateTagInput: (items: $ReadOnlyArray<AccountUserInfo>) => void,
   +resolveToUser: (user: AccountUserInfo) => void,
   +userSearchResults: $ReadOnlyArray<UserListItem>,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
-  +genesisThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+  +threadInfo: ThreadInfo,
+  +genesisThreadInfo: ?ThreadInfo,
   +messageListData: ?$ReadOnlyArray<NativeChatMessageItem>,
   +colors: Colors,
   +styles: $ReadOnly<typeof unboundStyles>,
diff --git a/native/chat/message-list-header-title.react.js b/native/chat/message-list-header-title.react.js
--- a/native/chat/message-list-header-title.react.js
+++ b/native/chat/message-list-header-title.react.js
@@ -6,7 +6,6 @@
 import { View } from 'react-native';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
 import { firstLine } from 'lib/utils/string-utils.js';
 
@@ -31,7 +30,7 @@
 };
 
 type BaseProps = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +navigate: $PropertyType<ChatNavigationProp<'MessageList'>, 'navigate'>,
   +isSearchEmpty: boolean,
   +areSettingsEnabled: boolean,
diff --git a/native/chat/message-list-types.js b/native/chat/message-list-types.js
--- a/native/chat/message-list-types.js
+++ b/native/chat/message-list-types.js
@@ -7,7 +7,6 @@
 
 import { useThreadChatMentionCandidates } from 'lib/hooks/chat-mention-hooks.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { type UserInfo } from 'lib/types/user-types.js';
 
 import { ChatContext } from './chat-context.js';
@@ -20,7 +19,7 @@
 } from '../navigation/route-names.js';
 
 export type MessageListParams = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +pendingPersonalThreadUserInfo?: UserInfo,
   +searching?: boolean,
   +removeEditMode?: ?RemoveEditMode,
@@ -37,7 +36,7 @@
 const MessageListContext: React.Context<?MessageListContextType> =
   React.createContext<?MessageListContextType>();
 
-function useMessageListContext(threadInfo: LegacyThreadInfo | ThreadInfo) {
+function useMessageListContext(threadInfo: ThreadInfo) {
   const chatMentionCandidates = useThreadChatMentionCandidates(threadInfo);
   const getTextMessageMarkdownRules = useTextMessageRulesFunc(
     threadInfo,
@@ -53,7 +52,7 @@
 
 type Props = {
   +children: React.Node,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 function MessageListContextProvider(props: Props): React.Node {
   const context = useMessageListContext(props.threadInfo);
@@ -96,7 +95,7 @@
 }
 
 function useNavigateToThreadWithFadeAnimation(
-  threadInfo: LegacyThreadInfo | ThreadInfo,
+  threadInfo: ThreadInfo,
   messageKey: ?string,
 ): () => mixed {
   const chatContext = React.useContext(ChatContext);
diff --git a/native/chat/message-result.react.js b/native/chat/message-result.react.js
--- a/native/chat/message-result.react.js
+++ b/native/chat/message-result.react.js
@@ -5,7 +5,6 @@
 import { ScrollView } from 'react-native-gesture-handler';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { longAbsoluteDate } from 'lib/utils/date-utils.js';
 
 import { type ChatNavigationProp } from './chat.react.js';
@@ -20,7 +19,7 @@
 
 type MessageResultProps = {
   +item: ChatMessageInfoItemWithHeight,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +navigation:
     | AppNavigationProp<'TogglePinModal'>
     | ChatNavigationProp<'MessageResultsScreen'>
diff --git a/native/chat/message-results-screen.react.js b/native/chat/message-results-screen.react.js
--- a/native/chat/message-results-screen.react.js
+++ b/native/chat/message-results-screen.react.js
@@ -16,7 +16,6 @@
 } from 'lib/shared/message-utils.js';
 import type { RawMessageInfo } from 'lib/types/message-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import { useHeightMeasurer } from './chat-context.js';
 import type { ChatNavigationProp } from './chat.react';
@@ -29,7 +28,7 @@
 import type { VerticalBounds } from '../types/layout-types.js';
 
 export type MessageResultsScreenParams = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 
 type MessageResultsScreenProps = {
diff --git a/native/chat/parent-thread-header.react.js b/native/chat/parent-thread-header.react.js
--- a/native/chat/parent-thread-header.react.js
+++ b/native/chat/parent-thread-header.react.js
@@ -6,7 +6,6 @@
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import type { ThreadType } from 'lib/types/thread-types-enum.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import { useNavigateToThread } from './message-list-types.js';
 import Button from '../components/button.react.js';
@@ -15,7 +14,7 @@
 import { useColors, useStyles } from '../themes/colors.js';
 
 type Props = {
-  +parentThreadInfo: LegacyThreadInfo | ThreadInfo,
+  +parentThreadInfo: ThreadInfo,
   +childThreadType: ThreadType,
 };
 function ParentThreadHeader(props: Props): React.Node {
diff --git a/native/chat/settings/compose-subchannel-modal.react.js b/native/chat/settings/compose-subchannel-modal.react.js
--- a/native/chat/settings/compose-subchannel-modal.react.js
+++ b/native/chat/settings/compose-subchannel-modal.react.js
@@ -7,7 +7,6 @@
 import { threadTypeDescriptions } from 'lib/shared/thread-utils.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import { threadTypes } from 'lib/types/thread-types-enum.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import Button from '../../components/button.react.js';
 import Modal from '../../components/modal.react.js';
@@ -19,7 +18,7 @@
 
 export type ComposeSubchannelModalParams = {
   +presentedFrom: string,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 
 const unboundStyles = {
diff --git a/native/chat/settings/thread-settings-child-thread.react.js b/native/chat/settings/thread-settings-child-thread.react.js
--- a/native/chat/settings/thread-settings-child-thread.react.js
+++ b/native/chat/settings/thread-settings-child-thread.react.js
@@ -4,7 +4,6 @@
 import { Platform, View } from 'react-native';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import ThreadAvatar from '../../avatars/thread-avatar.react.js';
 import Button from '../../components/button.react.js';
@@ -14,7 +13,7 @@
 import { useNavigateToThread } from '../message-list-types.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +firstListItem: boolean,
   +lastListItem: boolean,
 };
diff --git a/native/chat/settings/thread-settings-parent.react.js b/native/chat/settings/thread-settings-parent.react.js
--- a/native/chat/settings/thread-settings-parent.react.js
+++ b/native/chat/settings/thread-settings-parent.react.js
@@ -4,7 +4,6 @@
 import { Text, View } from 'react-native';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import ThreadAvatar from '../../avatars/thread-avatar.react.js';
 import Button from '../../components/button.react.js';
@@ -13,7 +12,7 @@
 import { useNavigateToThread } from '../message-list-types.js';
 
 type ParentButtonProps = {
-  +parentThreadInfo: LegacyThreadInfo | ThreadInfo,
+  +parentThreadInfo: ThreadInfo,
 };
 function ParentButton(props: ParentButtonProps): React.Node {
   const styles = useStyles(unboundStyles);
@@ -35,8 +34,8 @@
 }
 
 type ThreadSettingsParentProps = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
-  +parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+  +threadInfo: ThreadInfo,
+  +parentThreadInfo: ?ThreadInfo,
 };
 function ThreadSettingsParent(props: ThreadSettingsParentProps): React.Node {
   const { threadInfo, parentThreadInfo } = props;
diff --git a/native/chat/settings/thread-settings.react.js b/native/chat/settings/thread-settings.react.js
--- a/native/chat/settings/thread-settings.react.js
+++ b/native/chat/settings/thread-settings.react.js
@@ -40,11 +40,7 @@
 import type { RelationshipButton } from 'lib/types/relationship-types.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
 import { threadTypes } from 'lib/types/thread-types-enum.js';
-import type {
-  LegacyResolvedThreadInfo,
-  LegacyThreadInfo,
-  RelativeMemberInfo,
-} from 'lib/types/thread-types.js';
+import type { RelativeMemberInfo } from 'lib/types/thread-types.js';
 import type { UserInfos } from 'lib/types/user-types.js';
 import {
   useResolvedOptionalThreadInfo,
@@ -110,7 +106,7 @@
 const itemPageLength = 5;
 
 export type ThreadSettingsParams = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 
 export type ThreadSettingsNavigate = $PropertyType<
@@ -140,26 +136,20 @@
   | {
       +itemType: 'avatar',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +canChangeSettings: boolean,
     }
   | {
       +itemType: 'name',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +nameEditValue: ?string,
       +canChangeSettings: boolean,
     }
   | {
       +itemType: 'color',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +colorEditValue: string,
       +canChangeSettings: boolean,
       +navigate: ThreadSettingsNavigate,
@@ -168,9 +158,7 @@
   | {
       +itemType: 'description',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +descriptionEditValue: ?string,
       +descriptionTextHeight: ?number,
       +canChangeSettings: boolean,
@@ -178,34 +166,23 @@
   | {
       +itemType: 'parent',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
-      +parentThreadInfo: ?(
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo
-      ),
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
+      +parentThreadInfo: ?MinimallyEncodedResolvedThreadInfo,
     }
   | {
       +itemType: 'visibility',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
     }
   | {
       +itemType: 'pushNotifs',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
     }
   | {
       +itemType: 'homeNotifs',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
     }
   | {
       +itemType: 'seeMore',
@@ -215,9 +192,7 @@
   | {
       +itemType: 'childThread',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +firstListItem: boolean,
       +lastListItem: boolean,
     }
@@ -229,9 +204,7 @@
       +itemType: 'member',
       +key: string,
       +memberInfo: RelativeMemberInfo,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +canEdit: boolean,
       +navigate: ThreadSettingsNavigate,
       +firstListItem: boolean,
@@ -246,25 +219,21 @@
   | {
       +itemType: 'mediaGallery',
       +key: string,
-      +threadInfo: LegacyThreadInfo | ThreadInfo,
+      +threadInfo: ThreadInfo,
       +limit: number,
       +verticalBounds: ?VerticalBounds,
     }
   | {
       +itemType: 'promoteSidebar' | 'leaveThread' | 'deleteThread',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +navigate: ThreadSettingsNavigate,
       +buttonStyle: ViewStyle,
     }
   | {
       +itemType: 'editRelationship',
       +key: string,
-      +threadInfo:
-        | LegacyResolvedThreadInfo
-        | MinimallyEncodedResolvedThreadInfo,
+      +threadInfo: MinimallyEncodedResolvedThreadInfo,
       +navigate: ThreadSettingsNavigate,
       +buttonStyle: ViewStyle,
       +relationshipButton: RelationshipButton,
@@ -296,14 +265,9 @@
   // Redux state
   +userInfos: UserInfos,
   +viewerID: ?string,
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
-  +parentThreadInfo: ?(
-    | LegacyResolvedThreadInfo
-    | MinimallyEncodedResolvedThreadInfo
-  ),
-  +childThreadInfos: ?$ReadOnlyArray<
-    LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
-  >,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
+  +parentThreadInfo: ?MinimallyEncodedResolvedThreadInfo,
+  +childThreadInfos: ?$ReadOnlyArray<MinimallyEncodedResolvedThreadInfo>,
   +somethingIsSaving: boolean,
   +styles: $ReadOnly<typeof unboundStyles>,
   +indicatorStyle: IndicatorStyle,
@@ -381,13 +345,8 @@
       (propsAndState: PropsAndState) => propsAndState.navigation.navigate,
       (propsAndState: PropsAndState) => propsAndState.route.key,
       (
-        threadInfo:
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo,
-        parentThreadInfo: ?(
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo
-        ),
+        threadInfo: MinimallyEncodedResolvedThreadInfo,
+        parentThreadInfo: ?MinimallyEncodedResolvedThreadInfo,
         nameEditValue: ?string,
         colorEditValue: string,
         descriptionEditValue: ?string,
@@ -542,13 +501,9 @@
       (propsAndState: PropsAndState) => propsAndState.childThreadInfos,
       (propsAndState: PropsAndState) => propsAndState.numSubchannelsShowing,
       (
-        threadInfo:
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo,
+        threadInfo: MinimallyEncodedResolvedThreadInfo,
         navigate: ThreadSettingsNavigate,
-        childThreads: ?$ReadOnlyArray<
-          LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
-        >,
+        childThreads: ?$ReadOnlyArray<MinimallyEncodedResolvedThreadInfo>,
         numSubchannelsShowing: number,
       ) => {
         const listData: ChatSettingsItem[] = [];
@@ -613,9 +568,7 @@
       (propsAndState: PropsAndState) => propsAndState.numSidebarsShowing,
       (
         navigate: ThreadSettingsNavigate,
-        childThreads: ?$ReadOnlyArray<
-          LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
-        >,
+        childThreads: ?$ReadOnlyArray<MinimallyEncodedResolvedThreadInfo>,
         numSidebarsShowing: number,
       ) => {
         const listData: ChatSettingsItem[] = [];
@@ -674,9 +627,7 @@
       (propsAndState: PropsAndState) => propsAndState.numMembersShowing,
       (propsAndState: PropsAndState) => propsAndState.verticalBounds,
       (
-        threadInfo:
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo,
+        threadInfo: MinimallyEncodedResolvedThreadInfo,
         canStartEditing: boolean,
         navigate: ThreadSettingsNavigate,
         routeKey: string,
@@ -747,10 +698,7 @@
     createSelector(
       (propsAndState: PropsAndState) => propsAndState.threadInfo,
       (propsAndState: PropsAndState) => propsAndState.verticalBounds,
-      (
-        threadInfo: LegacyThreadInfo | ThreadInfo,
-        verticalBounds: ?VerticalBounds,
-      ) => {
+      (threadInfo: ThreadInfo, verticalBounds: ?VerticalBounds) => {
         const listData: ChatSettingsItem[] = [];
         const limit = 6;
 
@@ -789,13 +737,8 @@
       (propsAndState: PropsAndState) => propsAndState.userInfos,
       (propsAndState: PropsAndState) => propsAndState.viewerID,
       (
-        threadInfo:
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo,
-        parentThreadInfo: ?(
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo
-        ),
+        threadInfo: MinimallyEncodedResolvedThreadInfo,
+        parentThreadInfo: ?MinimallyEncodedResolvedThreadInfo,
         navigate: ThreadSettingsNavigate,
         styles: $ReadOnly<typeof unboundStyles>,
         userInfos: UserInfos,
@@ -1209,7 +1152,7 @@
     );
     const threadID = props.route.params.threadInfo.id;
 
-    const reduxThreadInfo: ?LegacyThreadInfo | ?ThreadInfo = useSelector(
+    const reduxThreadInfo: ?ThreadInfo = useSelector(
       state => threadInfoSelector(state)[threadID],
     );
     React.useEffect(() => {
@@ -1226,7 +1169,7 @@
         setParams({ threadInfo: reduxThreadInfo });
       }
     }, [reduxThreadInfo, setParams]);
-    const threadInfo: LegacyThreadInfo | ThreadInfo =
+    const threadInfo: ThreadInfo =
       reduxThreadInfo ?? props.route.params.threadInfo;
     const resolvedThreadInfo = useResolvedThreadInfo(threadInfo);
 
@@ -1241,9 +1184,8 @@
     }, [threadInfo]);
 
     const parentThreadID = threadInfo.parentThreadID;
-    const parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo = useSelector(
-      state =>
-        parentThreadID ? threadInfoSelector(state)[parentThreadID] : null,
+    const parentThreadInfo: ?ThreadInfo = useSelector(state =>
+      parentThreadID ? threadInfoSelector(state)[parentThreadID] : null,
     );
     const resolvedParentThreadInfo =
       useResolvedOptionalThreadInfo(parentThreadInfo);
diff --git a/native/chat/sidebar-navigation.js b/native/chat/sidebar-navigation.js
--- a/native/chat/sidebar-navigation.js
+++ b/native/chat/sidebar-navigation.js
@@ -11,10 +11,7 @@
   createUnresolvedPendingSidebar,
 } from 'lib/shared/thread-utils.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type {
-  ChatMentionCandidates,
-  LegacyThreadInfo,
-} from 'lib/types/thread-types.js';
+import type { ChatMentionCandidates } from 'lib/types/thread-types.js';
 import type { LoggedInUserInfo } from 'lib/types/user-types.js';
 import type { GetENSNames } from 'lib/utils/ens-helpers.js';
 
@@ -30,7 +27,7 @@
 };
 function getUnresolvedSidebarThreadInfo(
   input: GetUnresolvedSidebarThreadInfoInput,
-): ?LegacyThreadInfo | ?ThreadInfo {
+): ?ThreadInfo {
   const { sourceMessage, loggedInUserInfo, chatMentionCandidates } = input;
   const threadCreatedFromMessage = sourceMessage.threadCreatedFromMessage;
   if (threadCreatedFromMessage) {
@@ -57,7 +54,7 @@
 };
 async function getSidebarThreadInfo(
   input: GetSidebarThreadInfoInput,
-): Promise<?LegacyThreadInfo | ?ThreadInfo> {
+): Promise<?ThreadInfo> {
   const {
     sourceMessage,
     loggedInUserInfo,
diff --git a/native/chat/swipeable-thread.react.js b/native/chat/swipeable-thread.react.js
--- a/native/chat/swipeable-thread.react.js
+++ b/native/chat/swipeable-thread.react.js
@@ -8,15 +8,14 @@
 
 import useToggleUnreadStatus from 'lib/hooks/toggle-unread-status.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import Swipeable from '../components/swipeable.js';
 import { useColors } from '../themes/colors.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +mostRecentNonLocalMessage: ?string,
-  +onSwipeableWillOpen: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
+  +onSwipeableWillOpen: (threadInfo: ThreadInfo) => void,
   +currentlyOpenedSwipeableId?: string,
   +iconSize: number,
   +children: React.Node,
diff --git a/native/chat/thread-list-modal.react.js b/native/chat/thread-list-modal.react.js
--- a/native/chat/thread-list-modal.react.js
+++ b/native/chat/thread-list-modal.react.js
@@ -14,7 +14,7 @@
 import type { ChatThreadItem } from 'lib/selectors/chat-selectors.js';
 import type { SetState } from 'lib/types/hook-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo, SidebarInfo } from 'lib/types/thread-types.js';
+import type { SidebarInfo } from 'lib/types/thread-types.js';
 
 import { useNavigateToThread } from './message-list-types.js';
 import Modal from '../components/modal.react.js';
@@ -35,9 +35,9 @@
 }
 
 type Props<U> = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +createRenderItem: (
-    onPressItem: (threadInfo: LegacyThreadInfo | ThreadInfo) => void,
+    onPressItem: (threadInfo: ThreadInfo) => void,
   ) => (row: { +item: U, +index: number, ... }) => React.Node,
   +listData: $ReadOnlyArray<U>,
   +searchState: ThreadSearchState,
@@ -78,7 +78,7 @@
 
   const navigateToThread = useNavigateToThread();
   const onPressItem = React.useCallback(
-    (threadInfo: LegacyThreadInfo | ThreadInfo) => {
+    (threadInfo: ThreadInfo) => {
       setSearchState({
         text: '',
         results: new Set(),
diff --git a/native/chat/thread-settings-button.react.js b/native/chat/thread-settings-button.react.js
--- a/native/chat/thread-settings-button.react.js
+++ b/native/chat/thread-settings-button.react.js
@@ -3,7 +3,6 @@
 import * as React from 'react';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import type { ChatNavigationProp } from './chat.react.js';
 import Button from '../components/button.react.js';
@@ -19,7 +18,7 @@
 };
 
 type BaseProps = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +navigate: $PropertyType<ChatNavigationProp<'MessageList'>, 'navigate'>,
 };
 type Props = {
diff --git a/native/chat/thread-settings-header-title.react.js b/native/chat/thread-settings-header-title.react.js
--- a/native/chat/thread-settings-header-title.react.js
+++ b/native/chat/thread-settings-header-title.react.js
@@ -5,12 +5,11 @@
 import * as React from 'react';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
 import { firstLine } from 'lib/utils/string-utils.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   ...HeaderTitleInputProps,
 };
 function ThreadSettingsHeaderTitle(props: Props): React.Node {
diff --git a/native/chat/toggle-pin-modal.react.js b/native/chat/toggle-pin-modal.react.js
--- a/native/chat/toggle-pin-modal.react.js
+++ b/native/chat/toggle-pin-modal.react.js
@@ -10,7 +10,6 @@
 } from 'lib/actions/message-actions.js';
 import type { RawMessageInfo } from 'lib/types/message-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { useDispatchActionPromise } from 'lib/utils/redux-promise-utils.js';
 
 import MessageResult from './message-result.react.js';
@@ -23,7 +22,7 @@
 
 export type TogglePinModalParams = {
   +item: ChatMessageInfoItemWithHeight,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 
 type TogglePinModalProps = {
diff --git a/native/chat/utils.js b/native/chat/utils.js
--- a/native/chat/utils.js
+++ b/native/chat/utils.js
@@ -10,7 +10,6 @@
 import { messageKey } from 'lib/shared/message-utils.js';
 import { viewerIsMember } from 'lib/shared/thread-utils.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import { clusterEndHeight } from './chat-constants.js';
 import { ChatContext, useHeightMeasurer } from './chat-context.js';
@@ -101,7 +100,7 @@
   messageListVerticalBounds: VerticalBounds,
   currentInputBarHeight: number,
   targetInputBarHeight: number,
-  sidebarThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+  sidebarThreadInfo: ?ThreadInfo,
 ): {
   +position: number,
   +color: string,
diff --git a/native/components/community-pill.react.js b/native/components/community-pill.react.js
--- a/native/components/community-pill.react.js
+++ b/native/components/community-pill.react.js
@@ -5,7 +5,6 @@
 
 import { useKeyserverAdmin } from 'lib/shared/user-utils.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import CommIcon from './comm-icon.react.js';
 import Pill from './pill.react.js';
@@ -15,7 +14,7 @@
 const threadPillRoundCorners = { left: false, right: true };
 
 type Props = {
-  +community: LegacyThreadInfo | ThreadInfo,
+  +community: ThreadInfo,
 };
 function CommunityPill(props: Props): React.Node {
   const { community } = props;
diff --git a/native/components/thread-ancestors-label.react.js b/native/components/thread-ancestors-label.react.js
--- a/native/components/thread-ancestors-label.react.js
+++ b/native/components/thread-ancestors-label.react.js
@@ -6,13 +6,12 @@
 
 import { useAncestorThreads } from 'lib/shared/ancestor-threads.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { useResolvedThreadInfos } from 'lib/utils/entity-helpers.js';
 
 import { useColors, useStyles } from '../themes/colors.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 function ThreadAncestorsLabel(props: Props): React.Node {
   const { threadInfo } = props;
diff --git a/native/components/thread-ancestors.react.js b/native/components/thread-ancestors.react.js
--- a/native/components/thread-ancestors.react.js
+++ b/native/components/thread-ancestors.react.js
@@ -25,8 +25,9 @@
   const styles = useStyles(unboundStyles);
   const colors = useColors();
 
-  const ancestorThreads: $ReadOnlyArray<LegacyThreadInfo | ThreadInfo> =
-    useSelector(ancestorThreadInfos(threadInfo.id));
+  const ancestorThreads: $ReadOnlyArray<ThreadInfo> = useSelector(
+    ancestorThreadInfos(threadInfo.id),
+  );
 
   const rightArrow = React.useMemo(
     () => (
diff --git a/native/components/thread-list-thread.react.js b/native/components/thread-list-thread.react.js
--- a/native/components/thread-list-thread.react.js
+++ b/native/components/thread-list-thread.react.js
@@ -6,10 +6,6 @@
   MinimallyEncodedResolvedThreadInfo,
   ThreadInfo,
 } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type {
-  LegacyResolvedThreadInfo,
-  LegacyThreadInfo,
-} from 'lib/types/thread-types.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
 
 import Button from './button.react.js';
@@ -40,11 +36,11 @@
 };
 type BaseProps = {
   ...SharedProps,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 type Props = {
   ...SharedProps,
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +colors: Colors,
   +styles: $ReadOnly<typeof unboundStyles>,
 };
diff --git a/native/components/thread-list.react.js b/native/components/thread-list.react.js
--- a/native/components/thread-list.react.js
+++ b/native/components/thread-list.react.js
@@ -7,7 +7,6 @@
 
 import SearchIndex from 'lib/shared/search-index.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import Search from './search.react.js';
 import ThreadListThread from './thread-list-thread.react.js';
@@ -26,7 +25,7 @@
 };
 
 type BaseProps = {
-  +threadInfos: $ReadOnlyArray<LegacyThreadInfo | ThreadInfo>,
+  +threadInfos: $ReadOnlyArray<ThreadInfo>,
   +onSelect: (threadID: string) => void,
   +itemStyle?: ViewStyle,
   +itemTextStyle?: TextStyle,
@@ -50,27 +49,26 @@
   };
   textInput: ?React.ElementRef<typeof TextInput>;
 
-  listDataSelector: PropsAndState => $ReadOnlyArray<
-    LegacyThreadInfo | ThreadInfo,
-  > = createSelector(
-    (propsAndState: PropsAndState) => propsAndState.threadInfos,
-    (propsAndState: PropsAndState) => propsAndState.searchText,
-    (propsAndState: PropsAndState) => propsAndState.searchResults,
-    (propsAndState: PropsAndState) => propsAndState.itemStyle,
-    (propsAndState: PropsAndState) => propsAndState.itemTextStyle,
-    (
-      threadInfos: $ReadOnlyArray<LegacyThreadInfo | ThreadInfo>,
-      text: string,
-      searchResults: Set<string>,
-    ): $ReadOnlyArray<LegacyThreadInfo | ThreadInfo> =>
-      text
-        ? threadInfos.filter(threadInfo => searchResults.has(threadInfo.id))
-        : // We spread to make sure the result of this selector updates when
-          // any input param (namely itemStyle or itemTextStyle) changes
-          [...threadInfos],
-  );
-
-  get listData(): $ReadOnlyArray<LegacyThreadInfo | ThreadInfo> {
+  listDataSelector: PropsAndState => $ReadOnlyArray<ThreadInfo> =
+    createSelector(
+      (propsAndState: PropsAndState) => propsAndState.threadInfos,
+      (propsAndState: PropsAndState) => propsAndState.searchText,
+      (propsAndState: PropsAndState) => propsAndState.searchResults,
+      (propsAndState: PropsAndState) => propsAndState.itemStyle,
+      (propsAndState: PropsAndState) => propsAndState.itemTextStyle,
+      (
+        threadInfos: $ReadOnlyArray<ThreadInfo>,
+        text: string,
+        searchResults: Set<string>,
+      ): $ReadOnlyArray<ThreadInfo> =>
+        text
+          ? threadInfos.filter(threadInfo => searchResults.has(threadInfo.id))
+          : // We spread to make sure the result of this selector updates when
+            // any input param (namely itemStyle or itemTextStyle) changes
+            [...threadInfos],
+    );
+
+  get listData(): $ReadOnlyArray<ThreadInfo> {
     return this.listDataSelector({ ...this.props, ...this.state });
   }
 
@@ -103,14 +101,11 @@
     );
   }
 
-  static keyExtractor = (threadInfo: LegacyThreadInfo | ThreadInfo): string => {
+  static keyExtractor = (threadInfo: ThreadInfo): string => {
     return threadInfo.id;
   };
 
-  renderItem = (row: {
-    +item: LegacyThreadInfo | ThreadInfo,
-    ...
-  }): React.Node => {
+  renderItem = (row: { +item: ThreadInfo, ... }): React.Node => {
     return (
       <ThreadListThread
         threadInfo={row.item}
@@ -122,7 +117,7 @@
   };
 
   static getItemLayout = (
-    data: ?$ReadOnlyArray<LegacyThreadInfo | ThreadInfo>,
+    data: ?$ReadOnlyArray<ThreadInfo>,
     index: number,
   ): { length: number, offset: number, index: number } => {
     return { length: 24, offset: 24 * index, index };
diff --git a/native/components/thread-pill.react.js b/native/components/thread-pill.react.js
--- a/native/components/thread-pill.react.js
+++ b/native/components/thread-pill.react.js
@@ -3,13 +3,12 @@
 import * as React from 'react';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
 
 import Pill from './pill.react.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +roundCorners?: { +left: boolean, +right: boolean },
   +fontSize?: number,
 };
diff --git a/native/input/input-state-container.react.js b/native/input/input-state-container.react.js
--- a/native/input/input-state-container.react.js
+++ b/native/input/input-state-container.react.js
@@ -82,7 +82,6 @@
 import {
   type ClientNewThreadRequest,
   type NewThreadResult,
-  type LegacyThreadInfo,
 } from 'lib/types/thread-types.js';
 import { useLegacyAshoatKeyserverCall } from 'lib/utils/action-utils.js';
 import type {
@@ -174,10 +173,7 @@
   > = [];
   scrollToMessageCallbacks: Array<(messageID: string) => void> = [];
   pendingThreadCreations: Map<string, Promise<string>> = new Map();
-  pendingThreadUpdateHandlers: Map<
-    string,
-    (LegacyThreadInfo | ThreadInfo) => mixed,
-  > = new Map();
+  pendingThreadUpdateHandlers: Map<string, (ThreadInfo) => mixed> = new Map();
   // TODO: flip the switch
   // Note that this enables Blob service for encrypted media only
   useBlobServiceUploads = false;
@@ -450,8 +446,8 @@
 
   sendTextMessage = async (
     messageInfo: RawTextMessageInfo,
-    inputThreadInfo: LegacyThreadInfo | ThreadInfo,
-    parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+    inputThreadInfo: ThreadInfo,
+    parentThreadInfo: ?ThreadInfo,
   ) => {
     this.sendCallbacks.forEach(callback => callback());
 
@@ -547,9 +543,7 @@
     );
   };
 
-  startThreadCreation(
-    threadInfo: LegacyThreadInfo | ThreadInfo,
-  ): Promise<string> {
+  startThreadCreation(threadInfo: ThreadInfo): Promise<string> {
     if (!threadIsPending(threadInfo.id)) {
       return Promise.resolve(threadInfo.id);
     }
@@ -571,8 +565,8 @@
 
   async sendTextMessageAction(
     messageInfo: RawTextMessageInfo,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
-    parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+    threadInfo: ThreadInfo,
+    parentThreadInfo: ?ThreadInfo,
   ): Promise<SendMessagePayload> {
     try {
       await this.props.textMessageCreationSideEffectsFunc(
@@ -609,13 +603,13 @@
     }
   }
 
-  shouldEncryptMedia(threadInfo: LegacyThreadInfo | ThreadInfo): boolean {
+  shouldEncryptMedia(threadInfo: ThreadInfo): boolean {
     return threadInfoInsideCommunity(threadInfo, commStaffCommunity.id);
   }
 
   sendMultimediaMessage = async (
     selections: $ReadOnlyArray<NativeMediaSelection>,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
+    threadInfo: ThreadInfo,
   ) => {
     this.sendCallbacks.forEach(callback => callback());
     const localMessageID = this.props.nextLocalID;
@@ -716,7 +710,7 @@
   async uploadFiles(
     localMessageID: string,
     uploadFileInputs: $ReadOnlyArray<UploadFileInput>,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
+    threadInfo: ThreadInfo,
   ) {
     const results = await Promise.all(
       uploadFileInputs.map(uploadFileInput =>
@@ -732,7 +726,7 @@
   async uploadFile(
     localMessageID: string,
     uploadFileInput: UploadFileInput,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
+    threadInfo: ThreadInfo,
   ): Promise<?string> {
     const { ids, selection } = uploadFileInput;
     const { localMediaID } = ids;
@@ -1342,8 +1336,8 @@
 
   retryTextMessage = async (
     rawMessageInfo: RawTextMessageInfo,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
-    parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+    threadInfo: ThreadInfo,
+    parentThreadInfo: ?ThreadInfo,
   ) => {
     await this.sendTextMessage(
       {
@@ -1358,7 +1352,7 @@
   retryMultimediaMessage = async (
     rawMessageInfo: RawMultimediaMessageInfo,
     localMessageID: string,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
+    threadInfo: ThreadInfo,
   ): Promise<void> => {
     const pendingUploads = this.state.pendingUploads[localMessageID] ?? {};
 
@@ -1572,8 +1566,8 @@
 
   retryMessage = async (
     localMessageID: string,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
-    parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+    threadInfo: ThreadInfo,
+    parentThreadInfo: ?ThreadInfo,
   ) => {
     this.sendCallbacks.forEach(callback => callback());
 
@@ -1671,7 +1665,7 @@
 
   setPendingThreadUpdateHandler = (
     threadID: string,
-    pendingThreadUpdateHandler: ?(LegacyThreadInfo | ThreadInfo) => mixed,
+    pendingThreadUpdateHandler: ?(ThreadInfo) => mixed,
   ) => {
     if (!pendingThreadUpdateHandler) {
       this.pendingThreadUpdateHandlers.delete(threadID);
diff --git a/native/input/input-state.js b/native/input/input-state.js
--- a/native/input/input-state.js
+++ b/native/input/input-state.js
@@ -5,7 +5,6 @@
 import type { NativeMediaSelection } from 'lib/types/media-types.js';
 import type { RawTextMessageInfo } from 'lib/types/messages/text.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 export type MultimediaProcessingStep = 'transcoding' | 'uploading';
 
@@ -32,12 +31,12 @@
   +pendingUploads: PendingMultimediaUploads,
   +sendTextMessage: (
     messageInfo: RawTextMessageInfo,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
-    parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+    threadInfo: ThreadInfo,
+    parentThreadInfo: ?ThreadInfo,
   ) => Promise<void>,
   +sendMultimediaMessage: (
     selections: $ReadOnlyArray<NativeMediaSelection>,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
+    threadInfo: ThreadInfo,
   ) => Promise<void>,
   +editInputMessage: (params: EditInputBarMessageParameters) => void,
   +addEditInputMessageListener: (
@@ -49,8 +48,8 @@
   +messageHasUploadFailure: (localMessageID: string) => boolean,
   +retryMessage: (
     localMessageID: string,
-    threadInfo: LegacyThreadInfo | ThreadInfo,
-    parentThreadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+    threadInfo: ThreadInfo,
+    parentThreadInfo: ?ThreadInfo,
   ) => Promise<void>,
   +registerSendCallback: (() => void) => void,
   +unregisterSendCallback: (() => void) => void,
@@ -58,7 +57,7 @@
   +reportURIDisplayed: (uri: string, loaded: boolean) => void,
   +setPendingThreadUpdateHandler: (
     threadID: string,
-    pendingThreadUpdateHandler: ?(LegacyThreadInfo | ThreadInfo) => mixed,
+    pendingThreadUpdateHandler: ?(ThreadInfo) => mixed,
   ) => void,
   +scrollToMessage: (messageKey: string) => void,
   +addScrollToMessageListener: ((messageKey: string) => void) => void,
diff --git a/native/keyboard/keyboard-input-host.react.js b/native/keyboard/keyboard-input-host.react.js
--- a/native/keyboard/keyboard-input-host.react.js
+++ b/native/keyboard/keyboard-input-host.react.js
@@ -7,7 +7,6 @@
 
 import type { MediaLibrarySelection } from 'lib/types/media-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import { KeyboardContext, type KeyboardState } from './keyboard-state.js';
 import { type InputState, InputStateContext } from '../input/input-state.js';
@@ -76,7 +75,7 @@
     keyboardName: string,
     result: {
       +selections: $ReadOnlyArray<MediaLibrarySelection>,
-      +threadInfo: ?LegacyThreadInfo | ?ThreadInfo,
+      +threadInfo: ?ThreadInfo,
     },
   ) => {
     const { keyboardState } = this.props;
diff --git a/native/markdown/markdown-chat-mention.react.js b/native/markdown/markdown-chat-mention.react.js
--- a/native/markdown/markdown-chat-mention.react.js
+++ b/native/markdown/markdown-chat-mention.react.js
@@ -4,14 +4,13 @@
 import { Text, StyleSheet } from 'react-native';
 
 import type { MinimallyEncodedResolvedThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyResolvedThreadInfo } from 'lib/types/thread-types.js';
 
 import { useMarkdownOnPressUtils } from './markdown-utils.js';
 import { useNavigateToThreadWithFadeAnimation } from '../chat/message-list-types.js';
 
 type TextProps = React.ElementConfig<typeof Text>;
 type Props = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +children: React.Node,
   ...TextProps,
 };
diff --git a/native/media/chat-camera-modal.react.js b/native/media/chat-camera-modal.react.js
--- a/native/media/chat-camera-modal.react.js
+++ b/native/media/chat-camera-modal.react.js
@@ -5,7 +5,6 @@
 
 import type { PhotoCapture } from 'lib/types/media-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import CameraModal from './camera-modal.react.js';
 import { InputStateContext } from '../input/input-state.js';
@@ -14,7 +13,7 @@
 
 export type ChatCameraModalParams = {
   +presentedFrom: string,
-  +thread: LegacyThreadInfo | ThreadInfo,
+  +thread: ThreadInfo,
 };
 
 type Props = {
diff --git a/native/push/push-handler.react.js b/native/push/push-handler.react.js
--- a/native/push/push-handler.react.js
+++ b/native/push/push-handler.react.js
@@ -32,7 +32,6 @@
 import type { Dispatch } from 'lib/types/redux-types.js';
 import { type ConnectionInfo } from 'lib/types/socket-types.js';
 import type { GlobalTheme } from 'lib/types/theme-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import {
   convertNonPendingIDToNewSchema,
   convertNotificationMessageInfoToNewIDSchema,
@@ -106,7 +105,7 @@
     +[keyserverID: string]: ?string,
   },
   +threadInfos: {
-    +[id: string]: LegacyThreadInfo | ThreadInfo,
+    +[id: string]: ThreadInfo,
   },
   +notifPermissionAlertInfo: NotifPermissionAlertInfo,
   +connection: ConnectionInfo,
@@ -524,10 +523,7 @@
     );
   }
 
-  navigateToThread(
-    threadInfo: LegacyThreadInfo | ThreadInfo,
-    clearChatRoutes: boolean,
-  ) {
+  navigateToThread(threadInfo: ThreadInfo, clearChatRoutes: boolean) {
     if (clearChatRoutes) {
       this.props.navigation.dispatch({
         type: replaceWithThreadActionType,
diff --git a/native/search/message-search.react.js b/native/search/message-search.react.js
--- a/native/search/message-search.react.js
+++ b/native/search/message-search.react.js
@@ -13,7 +13,6 @@
 } from 'lib/shared/search-utils.js';
 import type { RawMessageInfo } from 'lib/types/message-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import SearchFooter from './search-footer.react.js';
 import { MessageSearchContext } from './search-provider.react.js';
@@ -29,7 +28,7 @@
 import type { VerticalBounds } from '../types/layout-types.js';
 
 export type MessageSearchParams = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 
 export type MessageSearchProps = {
diff --git a/native/search/search-messages-button.react.js b/native/search/search-messages-button.react.js
--- a/native/search/search-messages-button.react.js
+++ b/native/search/search-messages-button.react.js
@@ -3,7 +3,6 @@
 import * as React from 'react';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import type { ChatNavigationProp } from '../chat/chat.react.js';
 import Button from '../components/button.react.js';
@@ -12,7 +11,7 @@
 import { useStyles } from '../themes/colors.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +navigate: $PropertyType<ChatNavigationProp<'MessageList'>, 'navigate'>,
 };
 
diff --git a/native/selectors/calendar-selectors.js b/native/selectors/calendar-selectors.js
--- a/native/selectors/calendar-selectors.js
+++ b/native/selectors/calendar-selectors.js
@@ -9,7 +9,6 @@
 import { isLoggedIn } from 'lib/selectors/user-selectors.js';
 import type { EntryInfo } from 'lib/types/entry-types.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import { dateString } from 'lib/utils/date-utils.js';
 
 import type { AppState } from '../redux/state-types.js';
@@ -33,7 +32,7 @@
   | {
       itemType: 'entryInfo',
       entryInfo: EntryInfo,
-      threadInfo: LegacyThreadInfo | ThreadInfo,
+      threadInfo: ThreadInfo,
     };
 
 const calendarListData: (state: AppState) => ?(CalendarItem[]) = createSelector(
@@ -44,7 +43,7 @@
     loggedIn: boolean,
     daysToEntries: { +[dayString: string]: EntryInfo[] },
     threadInfos: {
-      +[id: string]: LegacyThreadInfo | ThreadInfo,
+      +[id: string]: ThreadInfo,
     },
   ) => {
     if (!loggedIn || daysToEntries[dateString(new Date())] === undefined) {
diff --git a/native/types/chat-types.js b/native/types/chat-types.js
--- a/native/types/chat-types.js
+++ b/native/types/chat-types.js
@@ -8,7 +8,6 @@
 } from 'lib/types/message-types.js';
 import type { TextMessageInfo } from 'lib/types/messages/text.js';
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import type { EntityText } from 'lib/utils/entity-text.js';
 
 import type { MessagePendingUploads } from '../input/input-state.js';
@@ -17,12 +16,12 @@
   +itemType: 'message',
   +messageShapeType: 'robotext',
   +messageInfo: RobotextMessageInfo,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +startsConversation: boolean,
   +startsCluster: boolean,
   +endsCluster: boolean,
   +robotext: EntityText,
-  +threadCreatedFromMessage: ?LegacyThreadInfo | ?ThreadInfo,
+  +threadCreatedFromMessage: ?ThreadInfo,
   +contentHeight: number,
   +reactions: ReactionInfo,
 };
@@ -32,12 +31,12 @@
   +messageShapeType: 'text',
   +messageInfo: TextMessageInfo,
   +localMessageInfo: ?LocalMessageInfo,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +startsConversation: boolean,
   +startsCluster: boolean,
   +endsCluster: boolean,
   +contentHeight: number,
-  +threadCreatedFromMessage: ?LegacyThreadInfo | ?ThreadInfo,
+  +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
   +hasBeenEdited: ?boolean,
   +isPinned: ?boolean,
@@ -57,11 +56,11 @@
   +messageShapeType: 'multimedia',
   +messageInfo: MultimediaMessageInfo,
   +localMessageInfo: ?LocalMessageInfo,
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +startsConversation: boolean,
   +startsCluster: boolean,
   +endsCluster: boolean,
-  +threadCreatedFromMessage: ?LegacyThreadInfo | ?ThreadInfo,
+  +threadCreatedFromMessage: ?ThreadInfo,
   +pendingUploads: ?MessagePendingUploads,
   +reactions: ReactionInfo,
   +hasBeenEdited: ?boolean,
diff --git a/native/user-profile/user-profile-message-button.react.js b/native/user-profile/user-profile-message-button.react.js
--- a/native/user-profile/user-profile-message-button.react.js
+++ b/native/user-profile/user-profile-message-button.react.js
@@ -5,7 +5,6 @@
 import { Text } from 'react-native';
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import type { UserInfo } from 'lib/types/user-types';
 
 import { useNavigateToThread } from '../chat/message-list-types.js';
@@ -14,7 +13,7 @@
 import { useStyles } from '../themes/colors.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +pendingPersonalThreadUserInfo?: UserInfo,
 };
 
diff --git a/native/utils/drawer-utils.react.js b/native/utils/drawer-utils.react.js
--- a/native/utils/drawer-utils.react.js
+++ b/native/utils/drawer-utils.react.js
@@ -2,13 +2,12 @@
 
 import type { ThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import { threadTypeIsCommunityRoot } from 'lib/types/thread-types-enum.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 import type { CommunityDrawerItemData } from 'lib/utils/drawer-utils.react.js';
 
 import type { TextStyle } from '../types/styles.js';
 
 export type CommunityDrawerItemDataFlattened = {
-  +threadInfo: LegacyThreadInfo | ThreadInfo,
+  +threadInfo: ThreadInfo,
   +hasSubchannelsButton: boolean,
   +labelStyle: TextStyle,
   +hasChildren: boolean,