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
@@ -212,7 +212,7 @@
     sidebarInfoSelector,
     (
       threadInfos: {
-        +[id: string]: LegacyThreadInfo | ThreadInfo,
+        +[id: string]: ThreadInfo,
       },
       messageStore: MessageStore,
       messageInfos: { +[id: string]: ?MessageInfo },
@@ -255,17 +255,15 @@
 }
 
 function getChatThreadItems(
-  threadInfos: { +[id: string]: LegacyThreadInfo | ThreadInfo },
+  threadInfos: { +[id: string]: ThreadInfo },
   messageStore: MessageStore,
   messageInfos: { +[id: string]: ?MessageInfo },
   sidebarInfos: { +[id: string]: $ReadOnlyArray<SidebarInfo> },
-  filterFunction: (
-    threadInfo: ?(LegacyThreadInfo | ThreadInfo | RawThreadInfo),
-  ) => boolean,
+  filterFunction: (threadInfo: ?(ThreadInfo | RawThreadInfo)) => boolean,
 ): $ReadOnlyArray<ChatThreadItem> {
   return _flow(
     _filter(filterFunction),
-    _map((threadInfo: LegacyThreadInfo | ThreadInfo): ChatThreadItem =>
+    _map((threadInfo: ThreadInfo): ChatThreadItem =>
       createChatThreadItem(
         threadInfo,
         messageStore,
@@ -317,9 +315,9 @@
   threadID: string,
   messageStore: MessageStore,
   messageInfos: { +[id: string]: ?MessageInfo },
-  threadInfos: { +[id: string]: LegacyThreadInfo | ThreadInfo },
+  threadInfos: { +[id: string]: ThreadInfo },
   threadInfoFromSourceMessageID: {
-    +[id: string]: LegacyThreadInfo | ThreadInfo,
+    +[id: string]: ThreadInfo,
   },
   additionalMessages: $ReadOnlyArray<MessageInfo>,
   viewerID: string,
@@ -592,10 +590,10 @@
       messageStore: MessageStore,
       messageInfos: { +[id: string]: ?MessageInfo },
       threadInfos: {
-        +[id: string]: LegacyThreadInfo | ThreadInfo,
+        +[id: string]: ThreadInfo,
       },
       threadInfoFromSourceMessageID: {
-        +[id: string]: LegacyThreadInfo | ThreadInfo,
+        +[id: string]: ThreadInfo,
       },
       viewerID: ?string,
     ): ?(ChatMessageItem[]) => {