diff --git a/web/chat/chat-input-bar.react.js b/web/chat/chat-input-bar.react.js
--- a/web/chat/chat-input-bar.react.js
+++ b/web/chat/chat-input-bar.react.js
@@ -38,7 +38,6 @@
 import { messageTypes } from 'lib/types/message-types-enum.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
 import {
-  type LegacyThreadInfo,
   type ClientThreadJoinRequest,
   type ThreadJoinPayload,
   type ThreadInfo,
@@ -84,7 +83,7 @@
   +joinThread: (request: ClientThreadJoinRequest) => Promise<ThreadJoinPayload>,
   +typeaheadMatchedStrings: ?TypeaheadMatchedStrings,
   +suggestions: $ReadOnlyArray<MentionTypeaheadSuggestionItem>,
-  +parentThreadInfo: ?LegacyThreadInfo,
+  +parentThreadInfo: ?ThreadInfo,
 };
 
 class ChatInputBar extends React.PureComponent<Props> {
diff --git a/web/chat/failed-send.react.js b/web/chat/failed-send.react.js
--- a/web/chat/failed-send.react.js
+++ b/web/chat/failed-send.react.js
@@ -11,7 +11,7 @@
   type RawComposableMessageInfo,
   assertComposableMessageType,
 } from 'lib/types/message-types.js';
-import type { LegacyThreadInfo, ThreadInfo } from 'lib/types/thread-types.js';
+import type { ThreadInfo } from 'lib/types/thread-types.js';
 
 import css from './chat-message-list.css';
 import multimediaMessageSendFailed from './multimedia-message-send-failed.js';
@@ -28,7 +28,7 @@
   ...BaseProps,
   +rawMessageInfo: RawComposableMessageInfo,
   +inputState: ?InputState,
-  +parentThreadInfo: ?LegacyThreadInfo,
+  +parentThreadInfo: ?ThreadInfo,
 };
 class FailedSend extends React.PureComponent<Props> {
   retryingText = false;
diff --git a/web/chat/message-preview.react.js b/web/chat/message-preview.react.js
--- a/web/chat/message-preview.react.js
+++ b/web/chat/message-preview.react.js
@@ -7,14 +7,14 @@
 import { useThreadChatMentionCandidates } from 'lib/hooks/chat-mention-hooks.js';
 import { useMessagePreview } from 'lib/shared/message-utils.js';
 import { type MessageInfo } from 'lib/types/message-types.js';
-import { type LegacyThreadInfo } from 'lib/types/thread-types.js';
+import type { ThreadInfo } from 'lib/types/thread-types.js';
 
 import css from './chat-thread-list.css';
 import { getDefaultTextMessageRules } from '../markdown/rules.react.js';
 
 type Props = {
   +messageInfo: ?MessageInfo,
-  +threadInfo: LegacyThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 function MessagePreview(props: Props): React.Node {
   const { messageInfo, threadInfo } = props;
diff --git a/web/input/input-state-container.react.js b/web/input/input-state-container.react.js
--- a/web/input/input-state-container.react.js
+++ b/web/input/input-state-container.react.js
@@ -79,7 +79,6 @@
 import {
   type ClientNewThreadRequest,
   type NewThreadResult,
-  type LegacyThreadInfo,
   type ThreadInfo,
 } from 'lib/types/thread-types.js';
 import {
@@ -420,7 +419,7 @@
     return rawMessageInfo;
   }
 
-  shouldEncryptMedia(threadInfo: LegacyThreadInfo): boolean {
+  shouldEncryptMedia(threadInfo: ThreadInfo): boolean {
     return threadInfoInsideCommunity(threadInfo, commStaffCommunity.id);
   }
 
@@ -627,20 +626,20 @@
             draft: draft ?? '',
             textCursorPosition: textCursorPosition ?? 0,
             appendFiles: (
-              threadInfo: LegacyThreadInfo,
+              threadInfo: ThreadInfo,
               files: $ReadOnlyArray<File>,
             ) => this.appendFiles(threadInfo, files),
             cancelPendingUpload: (localUploadID: string) =>
               this.cancelPendingUpload(threadID, localUploadID),
             sendTextMessage: (
               messageInfo: RawTextMessageInfo,
-              threadInfo: LegacyThreadInfo,
-              parentThreadInfo: ?LegacyThreadInfo,
+              threadInfo: ThreadInfo,
+              parentThreadInfo: ?ThreadInfo,
             ) =>
               this.sendTextMessage(messageInfo, threadInfo, parentThreadInfo),
             createMultimediaMessage: (
               localID: number,
-              threadInfo: LegacyThreadInfo,
+              threadInfo: ThreadInfo,
             ) => this.createMultimediaMessage(localID, threadInfo),
             setDraft: (newDraft: string) => this.setDraft(threadID, newDraft),
             setTextCursorPosition: (newPosition: number) =>
@@ -649,7 +648,7 @@
               this.messageHasUploadFailure(assignedUploads[localMessageID]),
             retryMultimediaMessage: (
               localMessageID: string,
-              threadInfo: LegacyThreadInfo,
+              threadInfo: ThreadInfo,
             ) =>
               this.retryMultimediaMessage(
                 localMessageID,
@@ -688,7 +687,7 @@
   }
 
   async appendFiles(
-    threadInfo: LegacyThreadInfo,
+    threadInfo: ThreadInfo,
     files: $ReadOnlyArray<File>,
   ): Promise<boolean> {
     const selectionTime = Date.now();
@@ -745,7 +744,7 @@
   }
 
   async appendFile(
-    threadInfo: LegacyThreadInfo,
+    threadInfo: ThreadInfo,
     file: File,
     selectTime: number,
   ): Promise<{
@@ -1380,7 +1379,7 @@
 
   // Creates a MultimediaMessage from the unassigned pending uploads,
   // if there are any
-  createMultimediaMessage(localID: number, threadInfo: LegacyThreadInfo) {
+  createMultimediaMessage(localID: number, threadInfo: ThreadInfo) {
     this.props.sendCallbacks.forEach(callback => callback());
 
     const localMessageID = `${localIDPrefix}${localID}`;
@@ -1501,7 +1500,7 @@
 
   retryMultimediaMessage(
     localMessageID: string,
-    threadInfo: LegacyThreadInfo,
+    threadInfo: ThreadInfo,
     pendingUploads: ?$ReadOnlyArray<PendingMultimediaUpload>,
   ) {
     this.props.sendCallbacks.forEach(callback => callback());
diff --git a/web/modals/threads/create/steps/subchannel-members.react.js b/web/modals/threads/create/steps/subchannel-members.react.js
--- a/web/modals/threads/create/steps/subchannel-members.react.js
+++ b/web/modals/threads/create/steps/subchannel-members.react.js
@@ -4,8 +4,7 @@
 
 import { userStoreSearchIndex } from 'lib/selectors/user-selectors.js';
 import { useAncestorThreads } from 'lib/shared/ancestor-threads.js';
-import type { MinimallyEncodedThreadInfo } from 'lib/types/minimally-encoded-thread-permissions-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
+import type { ThreadInfo } from 'lib/types/thread-types.js';
 
 import MembersList from './subchannel-members-list.react.js';
 import css from './subchannel-members.css';
@@ -13,7 +12,7 @@
 import { useSelector } from '../../../../redux/redux-utils.js';
 
 type SubchannelMembersProps = {
-  +parentThreadInfo: LegacyThreadInfo | MinimallyEncodedThreadInfo,
+  +parentThreadInfo: ThreadInfo,
   +selectedUsers: $ReadOnlySet<string>,
   +searchText: string,
   +setSearchText: string => void,
diff --git a/web/modals/threads/thread-picker-modal.react.js b/web/modals/threads/thread-picker-modal.react.js
--- a/web/modals/threads/thread-picker-modal.react.js
+++ b/web/modals/threads/thread-picker-modal.react.js
@@ -5,7 +5,7 @@
 
 import { useGlobalThreadSearchIndex } from 'lib/selectors/nav-selectors.js';
 import { onScreenEntryEditableThreadInfos } from 'lib/selectors/thread-selectors.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
+import type { ThreadInfo } from 'lib/types/thread-types.js';
 import { useResolvedThreadInfo } from 'lib/utils/entity-helpers.js';
 
 import css from './thread-picker-modal.css';
@@ -16,7 +16,7 @@
 import Modal, { type ModalOverridableProps } from '../modal.react.js';
 
 type OptionProps = {
-  +threadInfo: LegacyThreadInfo,
+  +threadInfo: ThreadInfo,
   +createNewEntry: (threadID: string) => void,
   +onCloseModal: () => void,
 };
diff --git a/web/modals/user-profile/user-profile-action-buttons.react.js b/web/modals/user-profile/user-profile-action-buttons.react.js
--- a/web/modals/user-profile/user-profile-action-buttons.react.js
+++ b/web/modals/user-profile/user-profile-action-buttons.react.js
@@ -5,7 +5,7 @@
 
 import { useRelationshipPrompt } from 'lib/hooks/relationship-prompt.js';
 import { userRelationshipStatus } from 'lib/types/relationship-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types';
+import type { ThreadInfo } from 'lib/types/thread-types';
 
 import UserProfileMessageButton from './user-profile-message-button.react.js';
 import css from './user-profile.css';
@@ -13,7 +13,7 @@
 import { buttonThemes } from '../../components/button.react.js';
 
 type Props = {
-  +threadInfo: LegacyThreadInfo,
+  +threadInfo: ThreadInfo,
 };
 
 function UserProfileActionButtons(props: Props): React.Node {
diff --git a/web/roles/create-roles-modal.react.js b/web/roles/create-roles-modal.react.js
--- a/web/roles/create-roles-modal.react.js
+++ b/web/roles/create-roles-modal.react.js
@@ -17,8 +17,8 @@
   userSurfacedPermissionOptions,
 } from 'lib/types/thread-permission-types.js';
 import type {
-  LegacyThreadInfo,
   RoleModificationRequest,
+  ThreadInfo,
 } from 'lib/types/thread-types.js';
 import { useDispatchActionPromise } from 'lib/utils/action-utils.js';
 import { values } from 'lib/utils/objects.js';
@@ -37,7 +37,7 @@
 );
 
 type CreateRolesModalProps = {
-  +threadInfo: LegacyThreadInfo,
+  +threadInfo: ThreadInfo,
   +action: 'create_role' | 'edit_role',
   +existingRoleID?: string,
   +roleName: string,
diff --git a/web/roles/delete-role-modal.react.js b/web/roles/delete-role-modal.react.js
--- a/web/roles/delete-role-modal.react.js
+++ b/web/roles/delete-role-modal.react.js
@@ -10,7 +10,7 @@
 import { createLoadingStatusSelector } from 'lib/selectors/loading-selectors.js';
 import { useRoleMemberCountsForCommunity } from 'lib/shared/thread-utils.js';
 import type { LoadingStatus } from 'lib/types/loading-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
+import type { ThreadInfo } from 'lib/types/thread-types.js';
 import { useDispatchActionPromise } from 'lib/utils/action-utils.js';
 import { constructRoleDeletionMessagePrompt } from 'lib/utils/role-utils.js';
 
@@ -24,7 +24,7 @@
 );
 
 type DeleteRoleModalProps = {
-  +threadInfo: LegacyThreadInfo,
+  +threadInfo: ThreadInfo,
   +defaultRoleID: string,
   +roleID: string,
 };
diff --git a/web/selectors/calendar-selectors.js b/web/selectors/calendar-selectors.js
--- a/web/selectors/calendar-selectors.js
+++ b/web/selectors/calendar-selectors.js
@@ -9,7 +9,7 @@
 import { threadInfoSelector } from 'lib/selectors/thread-selectors.js';
 import type SearchIndex from 'lib/shared/search-index.js';
 import type { FilterThreadInfo } from 'lib/types/filter-types.js';
-import type { LegacyThreadInfo } from 'lib/types/thread-types.js';
+import type { ThreadInfo } from 'lib/types/thread-types.js';
 import { filterThreadIDsBelongingToCommunity } from 'lib/utils/drawer-utils.react.js';
 
 import type { AppState } from '../redux/redux-setup.js';
@@ -32,7 +32,7 @@
   threadInfoSelector,
   (
     calendarPickedCommunityID: ?string,
-    threadInfos: { +[id: string]: LegacyThreadInfo },
+    threadInfos: { +[id: string]: ThreadInfo },
   ) => {
     if (!calendarPickedCommunityID) {
       return null;