diff --git a/lib/components/chat-mention-provider.react.js b/lib/components/chat-mention-provider.react.js
--- a/lib/components/chat-mention-provider.react.js
+++ b/lib/components/chat-mention-provider.react.js
@@ -13,7 +13,6 @@
 import type {
   ChatMentionCandidate,
   ChatMentionCandidatesObj,
-  LegacyResolvedThreadInfo,
   LegacyThreadInfo,
 } from '../types/thread-types.js';
 import { useResolvedThreadInfosObj } from '../utils/entity-helpers.js';
@@ -77,11 +76,9 @@
 }
 
 function getChatMentionCandidates(
-  threadInfos: { +[id: string]: LegacyThreadInfo | ThreadInfo },
+  threadInfos: { +[id: string]: ThreadInfo },
   resolvedThreadInfos: {
-    +[id: string]:
-      | LegacyResolvedThreadInfo
-      | MinimallyEncodedResolvedThreadInfo,
+    +[id: string]: MinimallyEncodedResolvedThreadInfo,
   },
 ): {
   chatMentionCandidatesObj: ChatMentionCandidatesObj,
@@ -219,9 +216,7 @@
 function useChatMentionCandidatesObjAndUtils(): {
   chatMentionCandidatesObj: ChatMentionCandidatesObj,
   resolvedThreadInfos: {
-    +[id: string]:
-      | LegacyResolvedThreadInfo
-      | MinimallyEncodedResolvedThreadInfo,
+    +[id: string]: MinimallyEncodedResolvedThreadInfo,
   },
   communityThreadIDForGenesisThreads: { +[id: string]: string },
 } {
diff --git a/lib/shared/markdown.js b/lib/shared/markdown.js
--- a/lib/shared/markdown.js
+++ b/lib/shared/markdown.js
@@ -11,7 +11,6 @@
 import type { MinimallyEncodedResolvedThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
 import type {
   ChatMentionCandidates,
-  LegacyResolvedThreadInfo,
   RelativeMemberInfo,
 } from '../types/thread-types.js';
 
@@ -286,7 +285,7 @@
   chatMentionCandidates: ChatMentionCandidates,
   capture: Capture,
 ): {
-  threadInfo: ?(LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo),
+  threadInfo: ?MinimallyEncodedResolvedThreadInfo,
   content: string,
   hasAccessToChat: boolean,
 } {
diff --git a/lib/shared/mention-utils.js b/lib/shared/mention-utils.js
--- a/lib/shared/mention-utils.js
+++ b/lib/shared/mention-utils.js
@@ -14,7 +14,6 @@
 import { threadTypes } from '../types/thread-types-enum.js';
 import type {
   ChatMentionCandidates,
-  LegacyResolvedThreadInfo,
   LegacyThreadInfo,
   RelativeMemberInfo,
 } from '../types/thread-types.js';
@@ -37,7 +36,7 @@
 
 type MentionTypeaheadChatSuggestionItem = {
   +type: 'chat',
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
 };
 
 export type MentionTypeaheadSuggestionItem =
@@ -78,7 +77,7 @@
 }
 
 function getRawChatMention(
-  threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  threadInfo: MinimallyEncodedResolvedThreadInfo,
 ): string {
   return `@[[${threadInfo.id}:${encodeChatMentionText(threadInfo.uiName)}]]`;
 }
diff --git a/lib/shared/mention-utils.test.js b/lib/shared/mention-utils.test.js
--- a/lib/shared/mention-utils.test.js
+++ b/lib/shared/mention-utils.test.js
@@ -7,7 +7,6 @@
   renderChatMentionsWithAltText,
 } from './mention-utils.js';
 import type { MinimallyEncodedResolvedThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyResolvedThreadInfo } from '../types/thread-types.js';
 
 describe('encodeChatMentionText', () => {
   it('should encode closing brackets', () => {
@@ -37,9 +36,7 @@
   it('should return raw chat mention', () =>
     expect(
       getRawChatMention({
-        ...(({}: any):
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo),
+        ...(({}: any): MinimallyEncodedResolvedThreadInfo),
         id: '256|123',
         uiName: 'thread-name',
       }),
@@ -48,9 +45,7 @@
   it('should return raw chat mention with encoded text', () =>
     expect(
       getRawChatMention({
-        ...(({}: any):
-          | LegacyResolvedThreadInfo
-          | MinimallyEncodedResolvedThreadInfo),
+        ...(({}: any): MinimallyEncodedResolvedThreadInfo),
         id: '256|123',
         uiName: 'thread-]name]]',
       }),
diff --git a/lib/types/filter-types.js b/lib/types/filter-types.js
--- a/lib/types/filter-types.js
+++ b/lib/types/filter-types.js
@@ -3,7 +3,6 @@
 import t, { type TUnion } from 'tcomb';
 
 import type { MinimallyEncodedResolvedThreadInfo } from './minimally-encoded-thread-permissions-types.js';
-import type { LegacyResolvedThreadInfo } from './thread-types.js';
 import { tID, tShape, tString } from '../utils/validation-utils.js';
 
 export const calendarThreadFilterTypes = Object.freeze({
@@ -42,6 +41,6 @@
 };
 
 export type FilterThreadInfo = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +numVisibleEntries: number,
 };
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
@@ -191,26 +191,6 @@
     pinnedCount: t.maybe(t.Number),
   });
 
-export type LegacyResolvedThreadInfo = {
-  +id: string,
-  +type: ThreadType,
-  +name: ?string,
-  +uiName: string,
-  +avatar?: ?ClientAvatar,
-  +description: ?string,
-  +color: string, // hex, without "#" or "0x"
-  +creationTime: number, // millisecond timestamp
-  +parentThreadID: ?string,
-  +containingThreadID: ?string,
-  +community: ?string,
-  +members: $ReadOnlyArray<LegacyRelativeMemberInfo>,
-  +roles: { +[id: string]: LegacyRoleInfo },
-  +currentUser: ThreadCurrentUserInfo,
-  +sourceMessageID?: string,
-  +repliesCount: number,
-  +pinnedCount?: number,
-};
-
 export type ServerMemberInfo = {
   +id: string,
   +role: ?string,
@@ -487,7 +467,7 @@
 export type ThreadStoreThreadInfos = LegacyRawThreadInfos;
 
 export type ChatMentionCandidate = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +rawChatName: string | ThreadEntity,
 };
 export type ChatMentionCandidates = {
diff --git a/lib/utils/drawer-utils.react.js b/lib/utils/drawer-utils.react.js
--- a/lib/utils/drawer-utils.react.js
+++ b/lib/utils/drawer-utils.react.js
@@ -10,10 +10,7 @@
   ThreadInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
 import { communitySubthreads } from '../types/thread-types-enum.js';
-import type {
-  LegacyResolvedThreadInfo,
-  LegacyThreadInfo,
-} from '../types/thread-types.js';
+import type { LegacyThreadInfo } from '../types/thread-types.js';
 
 type WritableCommunityDrawerItemData<T> = {
   threadInfo: ThreadInfo,
@@ -81,17 +78,10 @@
 }
 
 function useAppendCommunitySuffix(
-  communities: $ReadOnlyArray<
-    LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
-  >,
-): $ReadOnlyArray<
-  LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
-> {
+  communities: $ReadOnlyArray<MinimallyEncodedResolvedThreadInfo>,
+): $ReadOnlyArray<MinimallyEncodedResolvedThreadInfo> {
   return React.useMemo(() => {
-    const result: (
-      | LegacyResolvedThreadInfo
-      | MinimallyEncodedResolvedThreadInfo
-    )[] = [];
+    const result: MinimallyEncodedResolvedThreadInfo[] = [];
     const names = new Map<string, number>();
 
     for (const chat of communities) {
diff --git a/native/avatars/thread-avatar.react.js b/native/avatars/thread-avatar.react.js
--- a/native/avatars/thread-avatar.react.js
+++ b/native/avatars/thread-avatar.react.js
@@ -14,10 +14,7 @@
   ThreadInfo,
 } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import { threadTypes } from 'lib/types/thread-types-enum.js';
-import type {
-  LegacyResolvedThreadInfo,
-  LegacyThreadInfo,
-} from 'lib/types/thread-types.js';
+import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
 
 import Avatar from './avatar.react.js';
 import { useSelector } from '../redux/redux-utils.js';
@@ -27,7 +24,6 @@
     | RawThreadInfo
     | LegacyThreadInfo
     | ThreadInfo
-    | LegacyResolvedThreadInfo
     | MinimallyEncodedResolvedThreadInfo,
   +size: AvatarSize,
 };
diff --git a/native/chat/settings/delete-thread.react.js b/native/chat/settings/delete-thread.react.js
--- a/native/chat/settings/delete-thread.react.js
+++ b/native/chat/settings/delete-thread.react.js
@@ -31,7 +31,6 @@
 } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import type {
   LeaveThreadPayload,
-  LegacyResolvedThreadInfo,
   LegacyThreadInfo,
 } from 'lib/types/thread-types.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
@@ -118,7 +117,7 @@
 type Props = {
   ...BaseProps,
   // Redux state
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +shouldUseDeleteConfirmationAlert: boolean,
   +loadingStatus: LoadingStatus,
   +colors: Colors,
diff --git a/native/chat/settings/thread-settings-avatar.react.js b/native/chat/settings/thread-settings-avatar.react.js
--- a/native/chat/settings/thread-settings-avatar.react.js
+++ b/native/chat/settings/thread-settings-avatar.react.js
@@ -4,13 +4,12 @@
 import { View } 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 EditThreadAvatar from '../../avatars/edit-thread-avatar.react.js';
 import { useStyles } from '../../themes/colors.js';
 
 type Props = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +canChangeSettings: boolean,
 };
 function ThreadSettingsAvatar(props: Props): React.Node {
diff --git a/native/chat/settings/thread-settings-delete-thread.react.js b/native/chat/settings/thread-settings-delete-thread.react.js
--- a/native/chat/settings/thread-settings-delete-thread.react.js
+++ b/native/chat/settings/thread-settings-delete-thread.react.js
@@ -4,7 +4,6 @@
 import { Text, View } 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 type { ThreadSettingsNavigate } from './thread-settings.react.js';
 import Button from '../../components/button.react.js';
@@ -13,7 +12,7 @@
 import type { ViewStyle } from '../../types/styles.js';
 
 type Props = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +navigate: ThreadSettingsNavigate,
   +buttonStyle: ViewStyle,
 };
diff --git a/native/chat/settings/thread-settings-name.react.js b/native/chat/settings/thread-settings-name.react.js
--- a/native/chat/settings/thread-settings-name.react.js
+++ b/native/chat/settings/thread-settings-name.react.js
@@ -18,7 +18,6 @@
 import type { MinimallyEncodedResolvedThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
 import type {
   ChangeThreadSettingsPayload,
-  LegacyResolvedThreadInfo,
   UpdateThreadRequest,
 } from 'lib/types/thread-types.js';
 import {
@@ -62,7 +61,7 @@
 };
 
 type BaseProps = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +nameEditValue: ?string,
   +setNameEditValue: (value: ?string, callback?: () => void) => void,
   +canChangeSettings: boolean,
diff --git a/web/calendar/entry.react.js b/web/calendar/entry.react.js
--- a/web/calendar/entry.react.js
+++ b/web/calendar/entry.react.js
@@ -37,7 +37,6 @@
 import type { MinimallyEncodedResolvedThreadInfo } 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 } 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';
@@ -65,7 +64,7 @@
 };
 type Props = {
   ...BaseProps,
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +loggedIn: boolean,
   +calendarQuery: () => CalendarQuery,
   +online: boolean,
diff --git a/web/markdown/markdown-chat-mention.react.js b/web/markdown/markdown-chat-mention.react.js
--- a/web/markdown/markdown-chat-mention.react.js
+++ b/web/markdown/markdown-chat-mention.react.js
@@ -3,13 +3,12 @@
 import * as React from 'react';
 
 import type { MinimallyEncodedResolvedThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyResolvedThreadInfo } from 'lib/types/thread-types.js';
 
 import css from './markdown.css';
 import { useOnClickThread } from '../selectors/thread-selectors.js';
 
 type MarkdownChatMentionProps = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +hasAccessToChat: boolean,
   +text: string,
 };
diff --git a/web/modals/history/history-entry.react.js b/web/modals/history/history-entry.react.js
--- a/web/modals/history/history-entry.react.js
+++ b/web/modals/history/history-entry.react.js
@@ -21,7 +21,6 @@
 } from 'lib/types/entry-types.js';
 import type { LoadingStatus } from 'lib/types/loading-types.js';
 import type { MinimallyEncodedResolvedThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyResolvedThreadInfo } from 'lib/types/thread-types.js';
 import type { UserInfo } from 'lib/types/user-types.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
 import {
@@ -41,7 +40,7 @@
 };
 type Props = {
   ...BaseProps,
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
   +loggedIn: boolean,
   +restoreLoadingStatus: LoadingStatus,
   +calendarQuery: () => CalendarQuery,
diff --git a/web/navigation-sidebar/community-list-item.react.js b/web/navigation-sidebar/community-list-item.react.js
--- a/web/navigation-sidebar/community-list-item.react.js
+++ b/web/navigation-sidebar/community-list-item.react.js
@@ -4,7 +4,6 @@
 
 import { unreadCountSelectorForCommunity } from 'lib/selectors/thread-selectors.js';
 import type { MinimallyEncodedResolvedThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyResolvedThreadInfo } from 'lib/types/thread-types.js';
 
 import css from './community-list-item.css';
 import { navigationSidebarLabelTooltipMargin } from './navigation-sidebar-constants.js';
@@ -15,7 +14,7 @@
 import { tooltipPositions } from '../tooltips/tooltip-utils.js';
 
 type Props = {
-  +threadInfo: LegacyResolvedThreadInfo | MinimallyEncodedResolvedThreadInfo,
+  +threadInfo: MinimallyEncodedResolvedThreadInfo,
 };
 
 function CommunityListItem(props: Props): React.Node {