diff --git a/src/api/types/chats.ts b/src/api/types/chats.ts
index 7739caa56..6dc4acb49 100644
--- a/src/api/types/chats.ts
+++ b/src/api/types/chats.ts
@@ -1,4 +1,3 @@
-import type { ThreadId } from '../../types';
 import type { ApiBotCommand } from './bots';
 import type {
   ApiChatReactions, ApiFormattedText, ApiPhoto, ApiStickerSet,
@@ -48,10 +47,6 @@ export interface ApiChat {
   emojiStatus?: ApiEmojiStatus;
   isForum?: boolean;
   isForumAsMessages?: true;
-  topics?: Record<ThreadId, ApiTopic>;
-  listedTopicIds?: number[];
-  topicsCount?: number;
-  orderedPinnedTopicIds?: number[];
   boostLevel?: number;
 
   // Calls
diff --git a/src/components/common/ChatForumLastMessage.tsx b/src/components/common/ChatForumLastMessage.tsx
index 0be542f8d..abada322a 100644
--- a/src/components/common/ChatForumLastMessage.tsx
+++ b/src/components/common/ChatForumLastMessage.tsx
@@ -8,7 +8,7 @@ import React, {
 } from '../../lib/teact/teact';
 import { getActions } from '../../global';
 
-import type { ApiChat } from '../../api/types';
+import type { ApiChat, ApiTopic } from '../../api/types';
 import type { ObserveFn } from '../../hooks/useIntersectionObserver';
 
 import { getOrderedTopics } from '../../global/helpers';
@@ -26,6 +26,7 @@ import styles from './ChatForumLastMessage.module.scss';
 
 type OwnProps = {
   chat: ApiChat;
+  topics?: Record<number, ApiTopic>;
   renderLastMessage: () => React.ReactNode;
   observeIntersection?: ObserveFn;
 };
@@ -35,6 +36,7 @@ const MAX_TOPICS = 3;
 
 const ChatForumLastMessage: FC<OwnProps> = ({
   chat,
+  topics,
   renderLastMessage,
   observeIntersection,
 }) => {
@@ -48,12 +50,12 @@ const ChatForumLastMessage: FC<OwnProps> = ({
   const lang = useOldLang();
 
   const [lastActiveTopic, ...otherTopics] = useMemo(() => {
-    if (!chat.topics) {
+    if (!topics) {
       return [];
     }
 
-    return getOrderedTopics(Object.values(chat.topics), undefined, true).slice(0, MAX_TOPICS);
-  }, [chat.topics]);
+    return getOrderedTopics(Object.values(topics), undefined, true).slice(0, MAX_TOPICS);
+  }, [topics]);
 
   const [isReversedCorner, setIsReversedCorner] = useState(false);
   const [overwrittenWidth, setOverwrittenWidth] = useState<number | undefined>(undefined);
diff --git a/src/components/common/GroupChatInfo.tsx b/src/components/common/GroupChatInfo.tsx
index 56afbb05c..1055c5bfc 100644
--- a/src/components/common/GroupChatInfo.tsx
+++ b/src/components/common/GroupChatInfo.tsx
@@ -20,6 +20,7 @@ import {
   selectChatOnlineCount,
   selectThreadInfo,
   selectThreadMessagesCount,
+  selectTopic,
   selectUser,
 } from '../../global/selectors';
 import buildClassName from '../../util/buildClassName';
@@ -267,7 +268,7 @@ export default memo(withGlobal<OwnProps>(
     const threadInfo = threadId ? selectThreadInfo(global, chatId, threadId) : undefined;
     const onlineCount = chat ? selectChatOnlineCount(global, chat) : undefined;
     const areMessagesLoaded = Boolean(selectChatMessages(global, chatId));
-    const topic = threadId ? chat?.topics?.[threadId] : undefined;
+    const topic = threadId ? selectTopic(global, chatId, threadId) : undefined;
     const messagesCount = topic && selectThreadMessagesCount(global, chatId, threadId!);
     const self = selectUser(global, global.currentUserId!);
 
diff --git a/src/components/common/ProfileInfo.tsx b/src/components/common/ProfileInfo.tsx
index 396cb6a32..ee24b3e15 100644
--- a/src/components/common/ProfileInfo.tsx
+++ b/src/components/common/ProfileInfo.tsx
@@ -16,6 +16,7 @@ import {
   selectPeerPhotos,
   selectTabState,
   selectThreadMessagesCount,
+  selectTopic,
   selectUser,
   selectUserStatus,
 } from '../../global/selectors';
@@ -373,7 +374,7 @@ export default memo(withGlobal<OwnProps>(
     const { mediaIndex, chatId: avatarOwnerId } = selectTabState(global).mediaViewer;
     const isForum = chat?.isForum;
     const { threadId: currentTopicId } = selectCurrentMessageList(global) || {};
-    const topic = isForum && currentTopicId ? chat?.topics?.[currentTopicId] : undefined;
+    const topic = isForum && currentTopicId ? selectTopic(global, peerId, currentTopicId) : undefined;
 
     const emojiStatus = (user || chat)?.emojiStatus;
     const emojiStatusSticker = emojiStatus ? global.customEmojis.byId[emojiStatus.documentId] : undefined;
diff --git a/src/components/common/RecipientPicker.tsx b/src/components/common/RecipientPicker.tsx
index 0953ceecb..90aca7a68 100644
--- a/src/components/common/RecipientPicker.tsx
+++ b/src/components/common/RecipientPicker.tsx
@@ -4,7 +4,6 @@ import { getGlobal, withGlobal } from '../../global';
 
 import type { ApiChatType } from '../../api/types';
 import type { ThreadId } from '../../types';
-import { MAIN_THREAD_ID } from '../../api/types';
 
 import { API_CHAT_TYPES } from '../../config';
 import {
@@ -80,7 +79,7 @@ const RecipientPicker: FC<OwnProps & StateProps> = ({
       const user = usersById[id];
       if (user && isDeletedUser(user)) return false;
 
-      return chat && getCanPostInChat(chat, MAIN_THREAD_ID, undefined, chatFullInfoById[id]);
+      return chat && getCanPostInChat(chat, undefined, undefined, chatFullInfoById[id]);
     });
 
     const sorted = sortChatIds(
diff --git a/src/components/common/StickerSetModal.tsx b/src/components/common/StickerSetModal.tsx
index 7e9042907..6f38b7f1b 100644
--- a/src/components/common/StickerSetModal.tsx
+++ b/src/components/common/StickerSetModal.tsx
@@ -19,6 +19,7 @@ import {
   selectShouldSchedule,
   selectStickerSet,
   selectThreadInfo,
+  selectTopic,
 } from '../../global/selectors';
 import buildClassName from '../../util/buildClassName';
 import { copyTextToClipboard } from '../../util/clipboard';
@@ -263,8 +264,9 @@ export default memo(withGlobal<OwnProps>(
     const sendOptions = chat ? getAllowedAttachmentOptions(chat, chatFullInfo) : undefined;
     const threadInfo = chatId && threadId ? selectThreadInfo(global, chatId, threadId) : undefined;
     const isMessageThread = Boolean(!threadInfo?.isCommentsInfo && threadInfo?.fromChannelId);
+    const topic = chatId && threadId ? selectTopic(global, chatId, threadId) : undefined;
     const canSendStickers = Boolean(
-      chat && threadId && getCanPostInChat(chat, threadId, isMessageThread, chatFullInfo)
+      chat && threadId && getCanPostInChat(chat, topic, isMessageThread, chatFullInfo)
         && sendOptions?.canSendStickers,
     );
     const isSavedMessages = Boolean(chatId) && selectIsChatWithSelf(global, chatId);
diff --git a/src/components/common/pickers/ChatOrUserPicker.tsx b/src/components/common/pickers/ChatOrUserPicker.tsx
index a8d0fff86..f40f55806 100644
--- a/src/components/common/pickers/ChatOrUserPicker.tsx
+++ b/src/components/common/pickers/ChatOrUserPicker.tsx
@@ -13,7 +13,7 @@ import {
   getCanPostInChat, getGroupStatus, getUserStatus, isUserOnline,
 } from '../../../global/helpers';
 import { isApiPeerChat } from '../../../global/helpers/peers';
-import { selectChat, selectPeer, selectUserStatus } from '../../../global/selectors';
+import { selectPeer, selectTopics, selectUserStatus } from '../../../global/selectors';
 import buildClassName from '../../../util/buildClassName';
 import { REM } from '../helpers/mediaDimensions';
 import renderText from '../helpers/renderText';
@@ -94,15 +94,15 @@ const ChatOrUserPicker: FC<OwnProps> = ({
   useInputFocusOnOpen(searchRef, isOpen && activeKey === CHAT_LIST_SLIDE, resetSearch);
   useInputFocusOnOpen(topicSearchRef, isOpen && activeKey === TOPIC_LIST_SLIDE);
 
-  const selectTopics = useLastCallback((global: GlobalState) => {
+  const selectTopicsById = useLastCallback((global: GlobalState) => {
     if (!forumId) {
       return undefined;
     }
 
-    return selectChat(global, forumId)?.topics;
+    return selectTopics(global, forumId);
   });
 
-  const forumTopics = useSelector(selectTopics);
+  const forumTopicsById = useSelector(selectTopicsById);
 
   const [topicIds, topics] = useMemo(() => {
     const global = getGlobal();
@@ -111,16 +111,16 @@ const ChatOrUserPicker: FC<OwnProps> = ({
 
     const chat = chatsById[forumId!];
 
-    if (!chat || !forumTopics) {
+    if (!chat || !forumTopicsById) {
       return [undefined, undefined];
     }
 
     const searchTitle = topicSearch.toLowerCase();
 
-    const result = forumTopics
-      ? Object.values(forumTopics).reduce((acc, topic) => {
+    const result = forumTopicsById
+      ? Object.values(forumTopicsById).reduce((acc, topic) => {
         if (
-          getCanPostInChat(chat, topic.id, undefined, chatFullInfoById[forumId!])
+          getCanPostInChat(chat, topic, undefined, chatFullInfoById[forumId!])
           && (!searchTitle || topic.title.toLowerCase().includes(searchTitle))
         ) {
           acc[topic.id] = topic;
@@ -128,10 +128,10 @@ const ChatOrUserPicker: FC<OwnProps> = ({
 
         return acc;
       }, {} as Record<number, ApiTopic>)
-      : forumTopics;
+      : forumTopicsById;
 
     return [Object.keys(result).map(Number), result];
-  }, [forumId, topicSearch, forumTopics]);
+  }, [forumId, topicSearch, forumTopicsById]);
 
   const handleHeaderBackClick = useLastCallback(() => {
     setForumId(undefined);
@@ -153,7 +153,7 @@ const ChatOrUserPicker: FC<OwnProps> = ({
       const chatId = viewportIds[index === -1 ? 0 : index];
       const chat = chatsById[chatId];
       if (chat?.isForum) {
-        if (!chat.topics) loadTopics({ chatId });
+        if (!forumTopicsById) loadTopics({ chatId });
         setForumId(chatId);
       } else {
         onSelectChatOrUser(chatId);
@@ -171,7 +171,7 @@ const ChatOrUserPicker: FC<OwnProps> = ({
     const chatsById = getGlobal().chats.byId;
     const chat = chatsById?.[chatId];
     if (chat?.isForum) {
-      if (!chat.topics) loadTopics({ chatId });
+      if (!forumTopicsById) loadTopics({ chatId });
       setForumId(chatId);
       resetSearch();
     } else {
diff --git a/src/components/left/main/Chat.tsx b/src/components/left/main/Chat.tsx
index 7f7b283cf..177b868ef 100644
--- a/src/components/left/main/Chat.tsx
+++ b/src/components/left/main/Chat.tsx
@@ -43,6 +43,7 @@ import {
   selectTabState,
   selectThreadParam,
   selectTopicFromMessage,
+  selectTopicsInfo,
   selectUser,
   selectUserStatus,
 } from '../../../global/selectors';
@@ -90,6 +91,8 @@ type OwnProps = {
 
 type StateProps = {
   chat?: ApiChat;
+  listedTopicIds?: number[];
+  topics?: Record<number, ApiTopic>;
   isMuted?: boolean;
   user?: ApiUser;
   userStatus?: ApiUserStatus;
@@ -118,6 +121,8 @@ const Chat: FC<OwnProps & StateProps> = ({
   orderDiff,
   animationType,
   isPinned,
+  listedTopicIds,
+  topics,
   observeIntersection,
   chat,
   isMuted,
@@ -190,6 +195,7 @@ const Chat: FC<OwnProps & StateProps> = ({
     orderDiff,
     isSavedDialog,
     isPreview,
+    topics,
   });
 
   const getIsForumPanelClosed = useSelectorSignal(selectIsForumPanelClosed);
@@ -284,10 +290,10 @@ const Chat: FC<OwnProps & StateProps> = ({
 
   // Load the forum topics to display unread count badge
   useEffect(() => {
-    if (isIntersecting && isForum && chat && chat.listedTopicIds === undefined) {
+    if (isIntersecting && isForum && listedTopicIds === undefined) {
       loadTopics({ chatId });
     }
-  }, [chat, chatId, isForum, isIntersecting]);
+  }, [chatId, listedTopicIds, isForum, isIntersecting]);
 
   const isOnline = user && userStatus && isUserOnline(user, userStatus);
   const { hasShownClass: isAvatarOnlineShown } = useShowTransitionDeprecated(isOnline);
@@ -343,7 +349,13 @@ const Chat: FC<OwnProps & StateProps> = ({
         />
         <div className="avatar-badge-wrapper">
           <div className={buildClassName('avatar-online', isAvatarOnlineShown && 'avatar-online-shown')} />
-          <ChatBadge chat={chat} isMuted={isMuted} shouldShowOnlyMostImportant forceHidden={getIsForumPanelClosed} />
+          <ChatBadge
+            chat={chat}
+            isMuted={isMuted}
+            shouldShowOnlyMostImportant
+            forceHidden={getIsForumPanelClosed}
+            topics={topics}
+          />
         </div>
         {chat.isCallActive && chat.isCallNotEmpty && (
           <ChatCallStatus isMobile={isMobile} isSelected={isSelected} isActive={withInterfaceAnimations} />
@@ -376,6 +388,7 @@ const Chat: FC<OwnProps & StateProps> = ({
               isPinned={isPinned}
               isMuted={isMuted}
               isSavedDialog={isSavedDialog}
+              topics={topics}
             />
           )}
         </div>
@@ -460,6 +473,8 @@ export default memo(withGlobal<OwnProps>(
 
     const typingStatus = selectThreadParam(global, chatId, MAIN_THREAD_ID, 'typingStatus');
 
+    const topicsInfo = selectTopicsInfo(global, chatId);
+
     return {
       chat,
       isMuted: selectIsChatMuted(chat, selectNotifySettings(global), selectNotifyExceptions(global)),
@@ -484,6 +499,8 @@ export default memo(withGlobal<OwnProps>(
       lastMessage,
       lastMessageId,
       currentUserId: global.currentUserId!,
+      listedTopicIds: topicsInfo?.listedTopicIds,
+      topics: topicsInfo?.topicsById,
     };
   },
 )(Chat));
diff --git a/src/components/left/main/ChatBadge.tsx b/src/components/left/main/ChatBadge.tsx
index e39b9c291..6a83c52de 100644
--- a/src/components/left/main/ChatBadge.tsx
+++ b/src/components/left/main/ChatBadge.tsx
@@ -24,10 +24,19 @@ type OwnProps = {
   isSavedDialog?: boolean;
   shouldShowOnlyMostImportant?: boolean;
   forceHidden?: boolean | Signal<boolean>;
+  topics?: Record<number, ApiTopic>;
 };
 
 const ChatBadge: FC<OwnProps> = ({
-  topic, chat, isPinned, isMuted, shouldShowOnlyMostImportant, wasTopicOpened, forceHidden, isSavedDialog,
+  topic,
+  topics,
+  chat,
+  isPinned,
+  isMuted,
+  shouldShowOnlyMostImportant,
+  wasTopicOpened,
+  forceHidden,
+  isSavedDialog,
 }) => {
   const {
     unreadMentionsCount = 0, unreadReactionsCount = 0,
@@ -36,8 +45,8 @@ const ChatBadge: FC<OwnProps> = ({
   const isTopicUnopened = !isPinned && topic && !wasTopicOpened;
   const isForum = chat.isForum && !topic;
   const topicsWithUnread = useMemo(() => (
-    isForum && chat?.topics ? Object.values(chat.topics).filter(({ unreadCount }) => unreadCount) : undefined
-  ), [chat, isForum]);
+    isForum && topics ? Object.values(topics).filter(({ unreadCount }) => unreadCount) : undefined
+  ), [topics, isForum]);
 
   const unreadCount = useMemo(() => (
     isForum
@@ -48,11 +57,11 @@ const ChatBadge: FC<OwnProps> = ({
   ), [chat, topic, topicsWithUnread, isForum, isMuted]);
 
   const shouldBeMuted = useMemo(() => {
-    const hasUnmutedUnreadTopics = chat.topics
-      && Object.values(chat.topics).some((acc) => !acc.isMuted && acc.unreadCount);
+    const hasUnmutedUnreadTopics = topics
+      && Object.values(topics).some((acc) => !acc.isMuted && acc.unreadCount);
 
-    return isMuted || (chat.topics && !hasUnmutedUnreadTopics);
-  }, [chat, isMuted]);
+    return isMuted || (topics && !hasUnmutedUnreadTopics);
+  }, [topics, isMuted]);
 
   const hasUnreadMark = topic ? false : chat.hasUnreadMark;
 
diff --git a/src/components/left/main/ForumPanel.tsx b/src/components/left/main/ForumPanel.tsx
index 99c8b3068..3b983ae7b 100644
--- a/src/components/left/main/ForumPanel.tsx
+++ b/src/components/left/main/ForumPanel.tsx
@@ -6,6 +6,7 @@ import React, {
 import { getActions, withGlobal } from '../../../global';
 
 import type { ApiChat } from '../../../api/types';
+import type { TopicsInfo } from '../../../global/types';
 import { MAIN_THREAD_ID } from '../../../api/types';
 
 import {
@@ -14,7 +15,12 @@ import {
 import { requestNextMutation } from '../../../lib/fasterdom/fasterdom';
 import { getOrderedTopics } from '../../../global/helpers';
 import {
-  selectCanAnimateInterface, selectChat, selectCurrentMessageList, selectIsForumPanelOpen, selectTabState,
+  selectCanAnimateInterface,
+  selectChat,
+  selectCurrentMessageList,
+  selectIsForumPanelOpen,
+  selectTabState,
+  selectTopicsInfo,
 } from '../../../global/selectors';
 import buildClassName from '../../../util/buildClassName';
 import captureEscKeyListener from '../../../util/captureEscKeyListener';
@@ -52,6 +58,7 @@ type OwnProps = {
 
 type StateProps = {
   chat?: ApiChat;
+  topicsInfo?: TopicsInfo;
   currentTopicId?: number;
   withInterfaceAnimations?: boolean;
 };
@@ -63,6 +70,7 @@ const ForumPanel: FC<OwnProps & StateProps> = ({
   currentTopicId,
   isOpen,
   isHidden,
+  topicsInfo,
   onTopicSearch,
   onCloseAnimationEnd,
   onOpenAnimationStart,
@@ -80,12 +88,13 @@ const ForumPanel: FC<OwnProps & StateProps> = ({
   // eslint-disable-next-line no-null/no-null
   const scrollTopHandlerRef = useRef<HTMLDivElement>(null);
   const { isMobile } = useAppLayout();
+  const chatId = chat?.id;
 
   useEffect(() => {
-    if (chat && !chat.topics) {
-      loadTopics({ chatId: chat.id });
+    if (chatId && !topicsInfo) {
+      loadTopics({ chatId });
     }
-  }, [chat, loadTopics]);
+  }, [topicsInfo, chatId]);
 
   const [isScrolled, setIsScrolled] = useState(false);
   const lang = useOldLang();
@@ -115,17 +124,20 @@ const ForumPanel: FC<OwnProps & StateProps> = ({
   });
 
   const orderedIds = useMemo(() => {
-    return chat?.topics
-      ? getOrderedTopics(Object.values(chat.topics), chat.orderedPinnedTopicIds).map(({ id }) => id)
+    return topicsInfo
+      ? getOrderedTopics(
+        Object.values(topicsInfo.topicsById),
+        topicsInfo.orderedPinnedTopicIds,
+      ).map(({ id }) => id)
       : [];
-  }, [chat]);
+  }, [topicsInfo]);
 
   const { orderDiffById, getAnimationType } = useOrderDiff(orderedIds, chat?.id);
 
   const [viewportIds, getMore] = useInfiniteScroll(() => {
     if (!chat) return;
     loadTopics({ chatId: chat.id });
-  }, orderedIds, !chat?.topicsCount || orderedIds.length >= chat.topicsCount, TOPICS_SLICE);
+  }, orderedIds, !topicsInfo?.totalCount || orderedIds.length >= topicsInfo.totalCount, TOPICS_SLICE);
 
   const shouldRenderRef = useRef(false);
   const isVisible = isOpen && !isHidden;
@@ -191,7 +203,7 @@ const ForumPanel: FC<OwnProps & StateProps> = ({
       <Topic
         key={id}
         chatId={chat!.id}
-        topic={chat!.topics![id]}
+        topic={topicsInfo!.topicsById[id]}
         style={`top: ${(viewportOffset + i) * TOPIC_HEIGHT_PX}px;`}
         isSelected={currentTopicId === id}
         observeIntersection={observe}
@@ -201,7 +213,7 @@ const ForumPanel: FC<OwnProps & StateProps> = ({
     ));
   }
 
-  const isLoading = chat?.topics === undefined;
+  const isLoading = topicsInfo === undefined;
 
   return (
     <div
@@ -271,7 +283,7 @@ const ForumPanel: FC<OwnProps & StateProps> = ({
         )}
       </InfiniteScroll>
       {!isLoading && viewportIds?.length === 1 && viewportIds[0] === GENERAL_TOPIC_ID && (
-        <EmptyForum chatId={chat.id} />
+        <EmptyForum chatId={chatId!} />
       )}
     </div>
   );
@@ -285,11 +297,13 @@ export default memo(withGlobal<OwnProps>(
       chatId: currentChatId,
       threadId: currentThreadId,
     } = selectCurrentMessageList(global) || {};
+    const topicsInfo = chatId ? selectTopicsInfo(global, chatId) : undefined;
 
     return {
       chat,
       currentTopicId: chatId === currentChatId ? Number(currentThreadId) : undefined,
       withInterfaceAnimations: selectCanAnimateInterface(global),
+      topicsInfo,
     };
   },
   (global) => selectIsForumPanelOpen(global),
diff --git a/src/components/left/main/Topic.tsx b/src/components/left/main/Topic.tsx
index 5be750603..5143862da 100644
--- a/src/components/left/main/Topic.tsx
+++ b/src/components/left/main/Topic.tsx
@@ -22,6 +22,7 @@ import {
   selectOutgoingStatus,
   selectThreadInfo,
   selectThreadParam,
+  selectTopics,
   selectUser,
 } from '../../../global/selectors';
 import buildClassName from '../../../util/buildClassName';
@@ -68,6 +69,7 @@ type StateProps = {
   canScrollDown?: boolean;
   wasTopicOpened?: boolean;
   withInterfaceAnimations?: boolean;
+  topics?: Record<number, ApiTopic>;
 };
 
 const Topic: FC<OwnProps & StateProps> = ({
@@ -91,6 +93,7 @@ const Topic: FC<OwnProps & StateProps> = ({
   typingStatus,
   draft,
   wasTopicOpened,
+  topics,
 }) => {
   const {
     openThread,
@@ -138,6 +141,7 @@ const Topic: FC<OwnProps & StateProps> = ({
     observeIntersection,
     isTopic: true,
     typingStatus,
+    topics,
 
     animationType,
     withInterfaceAnimations,
@@ -208,6 +212,7 @@ const Topic: FC<OwnProps & StateProps> = ({
             isMuted={isMuted}
             topic={topic}
             wasTopicOpened={wasTopicOpened}
+            topics={topics}
           />
         </div>
       </div>
@@ -253,6 +258,7 @@ export default memo(withGlobal<OwnProps>(
     const draft = selectDraft(global, chatId, topic.id);
     const threadInfo = selectThreadInfo(global, chatId, topic.id);
     const wasTopicOpened = Boolean(threadInfo?.lastReadInboxMessageId);
+    const topics = selectTopics(global, chatId);
 
     const { chatId: currentChatId, threadId: currentThreadId } = selectCurrentMessageList(global) || {};
 
@@ -272,6 +278,7 @@ export default memo(withGlobal<OwnProps>(
       }),
       canScrollDown: isSelected && chat?.id === currentChatId && currentThreadId === topic.id,
       wasTopicOpened,
+      topics,
     };
   },
 )(Topic));
diff --git a/src/components/left/main/hooks/useChatListEntry.tsx b/src/components/left/main/hooks/useChatListEntry.tsx
index 7f65aeb86..81d348357 100644
--- a/src/components/left/main/hooks/useChatListEntry.tsx
+++ b/src/components/left/main/hooks/useChatListEntry.tsx
@@ -43,6 +43,7 @@ const ANIMATION_DURATION = 200;
 
 export default function useChatListEntry({
   chat,
+  topics,
   lastMessage,
   chatId,
   typingStatus,
@@ -61,6 +62,7 @@ export default function useChatListEntry({
   isPreview,
 }: {
   chat?: ApiChat;
+  topics?: Record<number, ApiTopic>;
   lastMessage?: ApiMessage;
   chatId: string;
   typingStatus?: ApiTypingStatus;
@@ -192,6 +194,7 @@ export default function useChatListEntry({
           chat={chat}
           renderLastMessage={renderLastMessageOrTyping}
           observeIntersection={observeIntersection}
+          topics={topics}
         />
       );
     }
diff --git a/src/components/left/search/LeftSearchResultTopic.tsx b/src/components/left/search/LeftSearchResultTopic.tsx
index 0302b4574..b6092bb6e 100644
--- a/src/components/left/search/LeftSearchResultTopic.tsx
+++ b/src/components/left/search/LeftSearchResultTopic.tsx
@@ -4,7 +4,7 @@ import { withGlobal } from '../../../global';
 
 import type { ApiTopic } from '../../../api/types';
 
-import { selectChat } from '../../../global/selectors';
+import { selectTopic } from '../../../global/selectors';
 import { REM } from '../../common/helpers/mediaDimensions';
 import renderText from '../../common/helpers/renderText';
 
@@ -60,8 +60,7 @@ const LeftSearchResultTopic: FC<OwnProps & StateProps> = ({
 
 export default memo(withGlobal<OwnProps>(
   (global, { chatId, topicId }): StateProps => {
-    const chat = selectChat(global, chatId);
-    const topic = chat?.topics?.[topicId];
+    const topic = selectTopic(global, chatId, topicId);
 
     return {
       topic,
diff --git a/src/components/main/GameModal.tsx b/src/components/main/GameModal.tsx
index aff998f11..0edfc78a8 100644
--- a/src/components/main/GameModal.tsx
+++ b/src/components/main/GameModal.tsx
@@ -4,7 +4,6 @@ import { getActions } from '../../lib/teact/teactn';
 import { withGlobal } from '../../global';
 
 import type { TabState } from '../../global/types';
-import { MAIN_THREAD_ID } from '../../api/types';
 
 import { getCanPostInChat } from '../../global/helpers';
 import { selectChat, selectChatFullInfo } from '../../global/selectors';
@@ -94,7 +93,7 @@ export default memo(withGlobal<OwnProps>(
     const { chatId } = openedGame || {};
     const chat = chatId && selectChat(global, chatId);
     const chatFullInfo = chatId ? selectChatFullInfo(global, chatId) : undefined;
-    const canPost = Boolean(chat) && getCanPostInChat(chat, MAIN_THREAD_ID, undefined, chatFullInfo);
+    const canPost = Boolean(chat) && getCanPostInChat(chat, undefined, undefined, chatFullInfo);
 
     return {
       canPost,
diff --git a/src/components/middle/HeaderMenuContainer.tsx b/src/components/middle/HeaderMenuContainer.tsx
index 6bca09a53..e1a8cdbb0 100644
--- a/src/components/middle/HeaderMenuContainer.tsx
+++ b/src/components/middle/HeaderMenuContainer.tsx
@@ -35,6 +35,7 @@ import {
   selectNotifyExceptions,
   selectNotifySettings,
   selectTabState,
+  selectTopic,
   selectUser,
   selectUserFullInfo,
 } from '../../global/selectors';
@@ -760,7 +761,7 @@ export default memo(withGlobal<OwnProps>(
       && !selectIsPremiumPurchaseBlocked(global),
     );
 
-    const topic = chat?.topics?.[threadId];
+    const topic = selectTopic(global, chatId, threadId);
     const canCreateTopic = chat.isForum && (
       chat.isCreator || !isUserRightBanned(chat, 'manageTopics') || getHasAdminRight(chat, 'manageTopics')
     );
diff --git a/src/components/middle/MessageList.tsx b/src/components/middle/MessageList.tsx
index e0334aae8..409eabce4 100644
--- a/src/components/middle/MessageList.tsx
+++ b/src/components/middle/MessageList.tsx
@@ -54,6 +54,7 @@ import {
   selectScrollOffset,
   selectTabState,
   selectThreadInfo,
+  selectTopic,
   selectUserFullInfo,
 } from '../../global/selectors';
 import animateScroll, { isAnimatingScroll, restartCurrentScrollAnimation } from '../../util/animateScroll';
@@ -772,7 +773,7 @@ export default memo(withGlobal<OwnProps>(
 
     const chatBot = selectBot(global, chatId);
 
-    const topic = chat.topics?.[threadId];
+    const topic = selectTopic(global, chatId, threadId);
     const chatFullInfo = !isUserId(chatId) ? selectChatFullInfo(global, chatId) : undefined;
     const isEmptyThread = !selectThreadInfo(global, chatId, threadId)?.messagesCount;
 
diff --git a/src/components/middle/MiddleColumn.tsx b/src/components/middle/MiddleColumn.tsx
index 995c33b2a..d4bdd8b53 100644
--- a/src/components/middle/MiddleColumn.tsx
+++ b/src/components/middle/MiddleColumn.tsx
@@ -4,7 +4,9 @@ import React, {
 } from '../../lib/teact/teact';
 import { getActions, withGlobal } from '../../global';
 
-import type { ApiChat, ApiChatBannedRights, ApiInputMessageReplyInfo } from '../../api/types';
+import type {
+  ApiChat, ApiChatBannedRights, ApiInputMessageReplyInfo, ApiTopic,
+} from '../../api/types';
 import type {
   ActiveEmojiInteraction,
   MessageListType,
@@ -55,6 +57,8 @@ import {
   selectTabState,
   selectTheme,
   selectThreadInfo,
+  selectTopic,
+  selectTopics,
   selectUserFullInfo,
 } from '../../global/selectors';
 import buildClassName from '../../util/buildClassName';
@@ -156,6 +160,7 @@ type StateProps = {
   isSavedDialog?: boolean;
   canShowOpenChatButton?: boolean;
   isContactRequirePremium?: boolean;
+  topics?: Record<number, ApiTopic>;
 };
 
 function isImage(item: DataTransferItem) {
@@ -217,6 +222,7 @@ function MiddleColumn({
   isSavedDialog,
   canShowOpenChatButton,
   isContactRequirePremium,
+  topics,
 }: OwnProps & StateProps) {
   const {
     openChat,
@@ -455,7 +461,7 @@ function MiddleColumn({
   const messageSendingRestrictionReason = getMessageSendingRestrictionReason(
     lang, currentUserBannedRights, defaultBannedRights,
   );
-  const forumComposerPlaceholder = getForumComposerPlaceholder(lang, chat, threadId, Boolean(draftReplyInfo));
+  const forumComposerPlaceholder = getForumComposerPlaceholder(lang, chat, threadId, topics, Boolean(draftReplyInfo));
 
   const composerRestrictionMessage = messageSendingRestrictionReason
     ?? forumComposerPlaceholder
@@ -775,7 +781,8 @@ export default memo(withGlobal<OwnProps>(
 
     const threadInfo = selectThreadInfo(global, chatId, threadId);
     const isMessageThread = Boolean(!threadInfo?.isCommentsInfo && threadInfo?.fromChannelId);
-    const canPost = chat && getCanPostInChat(chat, threadId, isMessageThread, chatFullInfo);
+    const topic = selectTopic(global, chatId, threadId);
+    const canPost = chat && getCanPostInChat(chat, topic, isMessageThread, chatFullInfo);
     const isBotNotStarted = selectIsChatBotNotStarted(global, chatId);
     const isPinnedMessageList = messageListType === 'pinned';
     const isMainThread = messageListType === 'thread' && threadId === MAIN_THREAD_ID;
@@ -794,11 +801,12 @@ export default memo(withGlobal<OwnProps>(
     );
     const draftReplyInfo = selectDraft(global, chatId, threadId)?.replyInfo;
     const shouldBlockSendInForum = chat?.isForum
-      ? threadId === MAIN_THREAD_ID && !draftReplyInfo && (chat.topics?.[GENERAL_TOPIC_ID]?.isClosed)
+      ? threadId === MAIN_THREAD_ID && !draftReplyInfo && (selectTopic(global, chatId, GENERAL_TOPIC_ID)?.isClosed)
       : false;
     const audioMessage = audioChatId && audioMessageId
       ? selectChatMessage(global, audioChatId, audioMessageId)
       : undefined;
+    const topics = selectTopics(global, chatId);
 
     const isSavedDialog = getIsSavedDialog(chatId, threadId, global.currentUserId);
     const canShowOpenChatButton = isSavedDialog && threadId !== ANONYMOUS_USER_ID;
@@ -854,6 +862,7 @@ export default memo(withGlobal<OwnProps>(
       isSavedDialog,
       canShowOpenChatButton,
       isContactRequirePremium,
+      topics,
     };
   },
 )(MiddleColumn));
diff --git a/src/components/middle/message/ContextMenuContainer.tsx b/src/components/middle/message/ContextMenuContainer.tsx
index 2d7c1677f..7cb2fe44a 100644
--- a/src/components/middle/message/ContextMenuContainer.tsx
+++ b/src/components/middle/message/ContextMenuContainer.tsx
@@ -54,6 +54,7 @@ import {
   selectRequestedMessageTranslationLanguage,
   selectStickerSet,
   selectThreadInfo,
+  selectTopic,
   selectUserStatus,
 } from '../../../global/selectors';
 import { copyTextToClipboard } from '../../../util/clipboard';
@@ -730,10 +731,11 @@ export default memo(withGlobal<OwnProps>(
 
     const threadInfo = threadId && selectThreadInfo(global, message.chatId, threadId);
     const isMessageThread = Boolean(threadInfo && !threadInfo?.isCommentsInfo && threadInfo?.fromChannelId);
+    const topic = threadId ? selectTopic(global, message.chatId, threadId) : undefined;
 
     const canSendText = chat && !isUserRightBanned(chat, 'sendPlain', chatFullInfo);
 
-    const canReplyInChat = chat && threadId ? getCanPostInChat(chat, threadId, isMessageThread, chatFullInfo)
+    const canReplyInChat = chat && threadId ? getCanPostInChat(chat, topic, isMessageThread, chatFullInfo)
      && canSendText : false;
 
     const isLocal = isMessageLocal(message);
diff --git a/src/components/middle/message/Message.tsx b/src/components/middle/message/Message.tsx
index feda1727f..9a8f14ba1 100644
--- a/src/components/middle/message/Message.tsx
+++ b/src/components/middle/message/Message.tsx
@@ -31,7 +31,7 @@ import type { PinnedIntersectionChangedCallback } from '../hooks/usePinnedMessag
 import { MAIN_THREAD_ID } from '../../../api/types';
 import { AudioOrigin } from '../../../types';
 
-import { EMOJI_STATUS_LOOP_LIMIT, GENERAL_TOPIC_ID } from '../../../config';
+import { EMOJI_STATUS_LOOP_LIMIT } from '../../../config';
 import {
   areReactionsEmpty,
   getIsDownloading,
@@ -1766,8 +1766,7 @@ export default memo(withGlobal<OwnProps>(
     const hasUnreadReaction = chat?.unreadReactions?.includes(message.id);
 
     const hasTopicChip = threadId === MAIN_THREAD_ID && chat?.isForum && isFirstInGroup;
-    const messageTopic = hasTopicChip ? (selectTopicFromMessage(global, message) || chat?.topics?.[GENERAL_TOPIC_ID])
-      : undefined;
+    const messageTopic = hasTopicChip ? selectTopicFromMessage(global, message) : undefined;
 
     const chatTranslations = selectChatTranslations(global, chatId);
 
diff --git a/src/components/right/EditTopic.tsx b/src/components/right/EditTopic.tsx
index 5feb9233e..864b50344 100644
--- a/src/components/right/EditTopic.tsx
+++ b/src/components/right/EditTopic.tsx
@@ -8,7 +8,9 @@ import type { ApiChat, ApiSticker, ApiTopic } from '../../api/types';
 import type { TabState } from '../../global/types';
 
 import { DEFAULT_TOPIC_ICON_STICKER_ID, GENERAL_TOPIC_ID } from '../../config';
-import { selectChat, selectIsCurrentUserPremium, selectTabState } from '../../global/selectors';
+import {
+  selectChat, selectIsCurrentUserPremium, selectTabState, selectTopic,
+} from '../../global/selectors';
 import buildClassName from '../../util/buildClassName';
 import { REM } from '../common/helpers/mediaDimensions';
 
@@ -185,7 +187,8 @@ export default memo(withGlobal(
   (global): StateProps => {
     const { editTopicPanel } = selectTabState(global);
     const chat = editTopicPanel?.chatId ? selectChat(global, editTopicPanel.chatId) : undefined;
-    const topic = editTopicPanel?.topicId ? chat?.topics?.[editTopicPanel?.topicId] : undefined;
+    const topic = editTopicPanel?.chatId && editTopicPanel?.topicId
+      ? selectTopic(global, editTopicPanel.chatId, editTopicPanel.topicId) : undefined;
 
     return {
       chat,
diff --git a/src/components/right/GifSearch.tsx b/src/components/right/GifSearch.tsx
index 9d16f557d..2320749d6 100644
--- a/src/components/right/GifSearch.tsx
+++ b/src/components/right/GifSearch.tsx
@@ -14,6 +14,7 @@ import {
   selectCurrentMessageList,
   selectIsChatWithBot,
   selectIsChatWithSelf, selectThreadInfo,
+  selectTopic,
 } from '../../global/selectors';
 import buildClassName from '../../util/buildClassName';
 import { IS_TOUCH_ENV } from '../../util/windowEnvironment';
@@ -174,8 +175,9 @@ export default memo(withGlobal(
     const isSavedMessages = Boolean(chatId) && selectIsChatWithSelf(global, chatId);
     const threadInfo = chatId && threadId ? selectThreadInfo(global, chatId, threadId) : undefined;
     const isMessageThread = Boolean(!threadInfo?.isCommentsInfo && threadInfo?.fromChannelId);
+    const topic = chatId && threadId ? selectTopic(global, chatId, threadId) : undefined;
     const canPostInChat = Boolean(chat) && Boolean(threadId)
-      && getCanPostInChat(chat, threadId, isMessageThread, chatFullInfo);
+      && getCanPostInChat(chat, topic, isMessageThread, chatFullInfo);
 
     return {
       query,
diff --git a/src/components/right/RightHeader.tsx b/src/components/right/RightHeader.tsx
index 8489fc8fa..69be19608 100644
--- a/src/components/right/RightHeader.tsx
+++ b/src/components/right/RightHeader.tsx
@@ -18,6 +18,7 @@ import {
   selectCurrentStickerSearch,
   selectIsChatWithSelf,
   selectTabState,
+  selectTopic,
   selectUser,
 } from '../../global/selectors';
 import buildClassName from '../../util/buildClassName';
@@ -582,7 +583,7 @@ export default withGlobal<OwnProps>(
     const user = isProfile && chatId && isUserId(chatId) ? selectUser(global, chatId) : undefined;
     const isChannel = chat && isChatChannel(chat);
     const isInsideTopic = chat?.isForum && Boolean(threadId && threadId !== MAIN_THREAD_ID);
-    const topic = isInsideTopic ? chat.topics?.[threadId!] : undefined;
+    const topic = isInsideTopic ? selectTopic(global, chatId!, threadId!) : undefined;
     const canEditTopic = isInsideTopic && topic && getCanManageTopic(chat, topic);
     const isBot = user && isUserBot(user);
     const isSavedMessages = chatId ? selectIsChatWithSelf(global, chatId) : undefined;
diff --git a/src/global/actions/api/chats.ts b/src/global/actions/api/chats.ts
index 944482642..93c75dfa3 100644
--- a/src/global/actions/api/chats.ts
+++ b/src/global/actions/api/chats.ts
@@ -112,6 +112,9 @@ import {
   selectTabState,
   selectThread,
   selectThreadInfo,
+  selectTopic,
+  selectTopics,
+  selectTopicsInfo,
   selectUser,
   selectUserByPhoneNumber,
 } from '../../selectors';
@@ -1169,7 +1172,9 @@ addActionHandler('markTopicRead', (global, actions, payload): ActionReturnType =
   const chat = selectChat(global, chatId);
   if (!chat) return;
 
-  const lastTopicMessageId = chat.topics?.[topicId]?.lastMessageId;
+  const topic = selectTopic(global, chatId, topicId);
+
+  const lastTopicMessageId = topic?.lastMessageId;
   if (!lastTopicMessageId) return;
 
   void callApi('markMessageListRead', {
@@ -2074,13 +2079,15 @@ addActionHandler('loadTopics', async (global, actions, payload): Promise<void> =
   const chat = selectChat(global, chatId);
   if (!chat) return;
 
-  if (!force && chat.listedTopicIds && chat.listedTopicIds.length === chat.topicsCount) {
+  const topicsInfo = selectTopicsInfo(global, chatId);
+
+  if (!force && topicsInfo?.listedTopicIds && topicsInfo.listedTopicIds.length === topicsInfo.totalCount) {
     return;
   }
 
-  const offsetTopic = !force && chat.listedTopicIds ? chat.listedTopicIds.reduce((acc, el) => {
-    const topic = chat.topics?.[el];
-    const accTopic = chat.topics?.[acc];
+  const offsetTopic = !force ? topicsInfo?.listedTopicIds?.reduce((acc, el) => {
+    const topic = selectTopic(global, chatId, el);
+    const accTopic = selectTopic(global, chatId, acc);
     if (!topic) return acc;
     if (!accTopic || topic.lastMessageId < accTopic.lastMessageId) {
       return el;
@@ -2089,7 +2096,7 @@ addActionHandler('loadTopics', async (global, actions, payload): Promise<void> =
   }) : undefined;
 
   const { id: offsetTopicId, date: offsetDate, lastMessageId: offsetId } = (offsetTopic
-    && chat.topics?.[offsetTopic]) || {};
+    && selectTopic(global, chatId, offsetTopic)) || {};
   const result = await callApi('fetchTopics', {
     chat, offsetTopicId, offsetId, offsetDate, limit: offsetTopicId ? TOPICS_SLICE : TOPICS_SLICE_SECOND_LOAD,
   });
@@ -2231,7 +2238,7 @@ addActionHandler('editTopic', async (global, actions, payload): Promise<void> =>
     chatId, topicId, tabId = getCurrentTabId(), ...rest
   } = payload;
   const chat = selectChat(global, chatId);
-  const topic = chat?.topics?.[topicId];
+  const topic = selectTopic(global, chatId, topicId);
   if (!chat || !topic) return;
 
   if (selectTabState(global, tabId).editTopicPanel) {
@@ -2262,9 +2269,10 @@ addActionHandler('toggleTopicPinned', (global, actions, payload): ActionReturnTy
 
   const { topicsPinnedLimit } = global.appConfig || {};
   const chat = selectChat(global, chatId);
-  if (!chat || !chat.topics || !topicsPinnedLimit) return;
+  const topics = selectTopics(global, chatId);
+  if (!chat || !topics || !topicsPinnedLimit) return;
 
-  if (isPinned && Object.values(chat.topics).filter((topic) => topic.isPinned).length >= topicsPinnedLimit) {
+  if (isPinned && Object.values(topics).filter((topic) => topic.isPinned).length >= topicsPinnedLimit) {
     actions.showNotification({
       message: langProvider.oldTranslate('LimitReachedPinnedTopics', topicsPinnedLimit, 'i'),
       tabId,
diff --git a/src/global/actions/api/messages.ts b/src/global/actions/api/messages.ts
index 94537592b..62ff7145e 100644
--- a/src/global/actions/api/messages.ts
+++ b/src/global/actions/api/messages.ts
@@ -127,6 +127,7 @@ import {
   selectSponsoredMessage,
   selectTabState,
   selectThreadIdFromMessage,
+  selectTopic,
   selectTranslationLanguage,
   selectUser,
   selectUserFullInfo,
@@ -907,8 +908,8 @@ addActionHandler('markMessageListRead', (global, actions, payload): ActionReturn
     return global;
   }
 
-  if (chat.isForum && chat.topics?.[threadId]) {
-    const topic = chat.topics[threadId];
+  const topic = selectTopic(global, chatId, threadId);
+  if (chat.isForum && topic) {
     global = updateThreadInfo(global, chatId, threadId, {
       lastReadInboxMessageId: maxId,
     });
diff --git a/src/global/actions/api/sync.ts b/src/global/actions/api/sync.ts
index fafe18897..e279fa729 100644
--- a/src/global/actions/api/sync.ts
+++ b/src/global/actions/api/sync.ts
@@ -36,6 +36,7 @@ import {
   selectEditingId,
   selectTabState,
   selectThreadInfo,
+  selectTopics,
 } from '../../selectors';
 
 const RELEASE_STATUS_TIMEOUT = 15000; // 15 sec;
@@ -160,10 +161,10 @@ async function loadAndReplaceMessages<T extends GlobalState>(global: T, actions:
         const localMessages = currentChatId === SERVICE_NOTIFICATIONS_USER_ID
           ? global.serviceNotifications.filter(({ isDeleted }) => !isDeleted).map(({ message }) => message)
           : [];
-        const topicLastMessages = currentChat.isForum && currentChat.topics
-          ? Object.values(currentChat.topics)
-            .map(({ lastMessageId }) => currentChatMessages[lastMessageId])
-            .filter(Boolean)
+        const topics = selectTopics(global, currentChatId);
+        const topicLastMessages = topics ? Object.values(topics)
+          .map(({ lastMessageId }) => currentChatMessages[lastMessageId])
+          .filter(Boolean)
           : [];
 
         const resultMessageIds = result.messages.map(({ id }) => id);
diff --git a/src/global/actions/apiUpdaters/chats.ts b/src/global/actions/apiUpdaters/chats.ts
index dd1faa4ee..e0dd02cda 100644
--- a/src/global/actions/apiUpdaters/chats.ts
+++ b/src/global/actions/apiUpdaters/chats.ts
@@ -17,6 +17,7 @@ import {
   leaveChat,
   removeUnreadMentions,
   replacePeerPhotos,
+  replacePinnedTopicIds,
   replaceThreadParam,
   updateChat,
   updateChatFullInfo,
@@ -482,9 +483,7 @@ addActionHandler('apiUpdate', (global, actions, update): ActionReturnType => {
       const chat = global.chats.byId[chatId];
       if (!chat) return undefined;
 
-      global = updateChat(global, chatId, {
-        orderedPinnedTopicIds: order,
-      });
+      global = replacePinnedTopicIds(global, chatId, order);
       setGlobal(global);
 
       return undefined;
diff --git a/src/global/actions/apiUpdaters/messages.ts b/src/global/actions/apiUpdaters/messages.ts
index c2d0744fd..793266c02 100644
--- a/src/global/actions/apiUpdaters/messages.ts
+++ b/src/global/actions/apiUpdaters/messages.ts
@@ -78,6 +78,7 @@ import {
   selectThreadByMessage,
   selectThreadIdFromMessage,
   selectThreadInfo,
+  selectTopic,
   selectTopicFromMessage,
   selectViewportIds,
 } from '../../selectors';
@@ -1061,7 +1062,7 @@ export function deleteMessages<T extends GlobalState>(
         isDeleting: true,
       });
 
-      if (chat.topics?.[id]) {
+      if (selectTopic(global, chatId, id)) {
         global = deleteTopic(global, chatId, id);
       }
 
@@ -1091,7 +1092,12 @@ export function deleteMessages<T extends GlobalState>(
       if (!threadInfo?.lastMessageId || !idsSet.has(threadInfo.lastMessageId)) return;
 
       const newLastMessage = findLastMessage(global, chatId, threadId);
-      if (!newLastMessage) return;
+      if (!newLastMessage) {
+        if (chat.isForum && threadId !== MAIN_THREAD_ID) {
+          actions.loadTopicById({ chatId, topicId: Number(threadId) });
+        }
+        return;
+      }
 
       if (threadId === MAIN_THREAD_ID) {
         global = updateChatLastMessage(global, chatId, newLastMessage, true);
diff --git a/src/global/actions/ui/misc.ts b/src/global/actions/ui/misc.ts
index 220f99a87..9138927f8 100644
--- a/src/global/actions/ui/misc.ts
+++ b/src/global/actions/ui/misc.ts
@@ -33,6 +33,7 @@ import {
   selectIsTrustedBot,
   selectSender,
   selectTabState,
+  selectTopic,
 } from '../../selectors';
 
 import { getIsMobile, getIsTablet } from '../../../hooks/useAppLayout';
@@ -773,8 +774,9 @@ addActionHandler('updatePageTitle', (global, actions, payload): ActionReturnType
     const currentChat = selectChat(global, chatId);
     if (currentChat) {
       const title = getChatTitle(langProvider.oldTranslate, currentChat, chatId === currentUserId);
-      if (currentChat.isForum && currentChat.topics?.[threadId]) {
-        setPageTitle(`${title} › ${currentChat.topics[threadId].title}`);
+      const topic = selectTopic(global, chatId, threadId);
+      if (currentChat.isForum && topic) {
+        setPageTitle(`${title} › ${topic.title}`);
         return;
       }
 
diff --git a/src/global/cache.ts b/src/global/cache.ts
index dfc26b25a..4c18eadb3 100644
--- a/src/global/cache.ts
+++ b/src/global/cache.ts
@@ -36,10 +36,10 @@ import { addActionHandler, getGlobal } from './index';
 import { INITIAL_GLOBAL_STATE, INITIAL_PERFORMANCE_STATE_MID, INITIAL_PERFORMANCE_STATE_MIN } from './initialState';
 import { clearGlobalForLockScreen } from './reducers';
 import {
-  selectChat,
   selectChatLastMessageId,
   selectChatMessages,
   selectCurrentMessageList,
+  selectTopics,
   selectViewportIds,
   selectVisibleUsers,
 } from './selectors';
@@ -248,6 +248,9 @@ function unsafeMigrateCache(cached: GlobalState, initialState: GlobalState) {
   if (!cached.users.commonChatsById) {
     cached.users.commonChatsById = initialState.users.commonChatsById;
   }
+  if (!cached.chats.topicsInfoById) {
+    cached.chats.topicsInfoById = initialState.chats.topicsInfoById;
+  }
 }
 
 function updateCache(force?: boolean) {
@@ -446,6 +449,7 @@ function reduceChats<T extends GlobalState>(global: T): GlobalState['chats'] {
       all: pickTruthy(global.chats.lastMessageIds.all || {}, idsToSave),
       saved: global.chats.lastMessageIds.saved,
     },
+    topicsInfoById: pickTruthy(global.chats.topicsInfoById, currentChatIds),
   };
 }
 
@@ -486,7 +490,6 @@ function reduceMessages<T extends GlobalState>(global: T): GlobalState['messages
       return;
     }
 
-    const chat = selectChat(global, chatId);
     const chatLastMessageId = selectChatLastMessageId(global, chatId);
 
     const openedThreadIds = Array.from(openedChatThreadIds[chatId] || []);
@@ -498,8 +501,9 @@ function reduceMessages<T extends GlobalState>(global: T): GlobalState['messages
     const threadsToSave = pickTruthy(current.threadsById, [MAIN_THREAD_ID, ...threadIds]);
 
     const viewportIdsToSave = unique(Object.values(threadsToSave).flatMap((thread) => thread.lastViewportIds || []));
-    const topicLastMessageIds = chat?.topics ? Object.values(chat.topics).map(({ lastMessageId }) => lastMessageId)
-      : [];
+    const topics = selectTopics(global, chatId);
+    const topicLastMessageIds = topics && forumPanelChatIds.includes(chatId)
+      ? Object.values(topics).map(({ lastMessageId }) => lastMessageId) : [];
     const savedLastMessageIds = chatId === currentUserId && global.chats.lastMessageIds.saved
       ? Object.values(global.chats.lastMessageIds.saved) : [];
     const lastMessageIdsToSave = [chatLastMessageId].concat(topicLastMessageIds).concat(savedLastMessageIds)
diff --git a/src/global/helpers/chats.ts b/src/global/helpers/chats.ts
index 7805a710c..2036d8451 100644
--- a/src/global/helpers/chats.ts
+++ b/src/global/helpers/chats.ts
@@ -145,15 +145,14 @@ export function isUserRightBanned(chat: ApiChat, key: keyof ApiChatBannedRights,
 }
 
 export function getCanPostInChat(
-  chat: ApiChat, threadId: ThreadId, isMessageThread?: boolean, chatFullInfo?: ApiChatFullInfo,
+  chat: ApiChat, topic?: ApiTopic, isMessageThread?: boolean, chatFullInfo?: ApiChatFullInfo,
 ) {
-  if (threadId !== MAIN_THREAD_ID) {
+  if (topic) {
     if (chat.isForum) {
       if (chat.isNotJoined) {
         return false;
       }
 
-      const topic = chat.topics?.[threadId];
       if (topic?.isClosed && !topic.isOwner && !getHasAdminRight(chat, 'manageTopics')) {
         return false;
       }
@@ -264,18 +263,22 @@ export function getMessageSendingRestrictionReason(
 }
 
 export function getForumComposerPlaceholder(
-  lang: LangFn, chat?: ApiChat, threadId: ThreadId = MAIN_THREAD_ID, isReplying?: boolean,
+  lang: LangFn,
+  chat?: ApiChat,
+  threadId: ThreadId = MAIN_THREAD_ID,
+  topics?: Record<number, ApiTopic>,
+  isReplying?: boolean,
 ) {
   if (!chat?.isForum) {
     return undefined;
   }
 
   if (threadId === MAIN_THREAD_ID) {
-    if (isReplying || (chat.topics && !chat.topics[GENERAL_TOPIC_ID]?.isClosed)) return undefined;
+    if (isReplying || (topics && !topics[GENERAL_TOPIC_ID]?.isClosed)) return undefined;
     return lang('lng_forum_replies_only');
   }
 
-  const topic = chat.topics?.[threadId];
+  const topic = topics?.[Number(threadId)];
   if (!topic) {
     return undefined;
   }
diff --git a/src/global/initialState.ts b/src/global/initialState.ts
index ced1595f1..40f1a0878 100644
--- a/src/global/initialState.ts
+++ b/src/global/initialState.ts
@@ -110,6 +110,7 @@ export const INITIAL_GLOBAL_STATE: GlobalState = {
     byId: {},
     fullInfoById: {},
     similarChannelsById: {},
+    topicsInfoById: {},
     loadingParameters: {
       active: {},
       archived: {},
diff --git a/src/global/reducers/chats.ts b/src/global/reducers/chats.ts
index afbbfd0f8..d2a5e7c43 100644
--- a/src/global/reducers/chats.ts
+++ b/src/global/reducers/chats.ts
@@ -1,5 +1,5 @@
 import type {
-  ApiChat, ApiChatFullInfo, ApiChatMember, ApiTopic,
+  ApiChat, ApiChatFullInfo, ApiChatMember,
 } from '../../api/types';
 import type { ChatListType, GlobalState } from '../types';
 
@@ -8,8 +8,7 @@ import { areDeepEqual } from '../../util/areDeepEqual';
 import {
   areSortedArraysEqual, buildCollectionByKey, omit, pick, unique,
 } from '../../util/iteratees';
-import { selectChat, selectChatFullInfo } from '../selectors';
-import { updateThread, updateThreadInfo } from './messages';
+import { selectChatFullInfo } from '../selectors';
 
 const DEFAULT_CHAT_LISTS: ChatListType[] = ['active', 'archived'];
 
@@ -423,95 +422,6 @@ export function addChatMembers<T extends GlobalState>(global: T, chat: ApiChat,
   });
 }
 
-export function updateListedTopicIds<T extends GlobalState>(
-  global: T, chatId: string, topicIds: number[],
-): T {
-  return updateChat(global, chatId, {
-    listedTopicIds: unique([
-      ...(global.chats.byId[chatId]?.listedTopicIds || []),
-      ...topicIds,
-    ]),
-  });
-}
-
-export function updateTopics<T extends GlobalState>(
-  global: T, chatId: string, topicsCount: number, topics: ApiTopic[],
-): T {
-  const chat = selectChat(global, chatId);
-
-  const newTopics = buildCollectionByKey(topics, 'id');
-
-  global = updateChat(global, chatId, {
-    topics: {
-      ...chat?.topics,
-      ...newTopics,
-    },
-    topicsCount,
-  });
-
-  topics.forEach((topic) => {
-    global = updateThread(global, chatId, topic.id, {
-      firstMessageId: topic.id,
-    });
-
-    global = updateThreadInfo(global, chatId, topic.id, {
-      lastMessageId: topic.lastMessageId,
-      threadId: topic.id,
-      chatId,
-    });
-  });
-
-  return global;
-}
-
-export function updateTopic<T extends GlobalState>(
-  global: T, chatId: string, topicId: number, update: Partial<ApiTopic>,
-): T {
-  const chat = selectChat(global, chatId);
-
-  if (!chat) return global;
-
-  const topic = chat?.topics?.[topicId];
-
-  const updatedTopic = {
-    ...topic,
-    ...update,
-  } as ApiTopic;
-
-  if (!updatedTopic.id) return global;
-
-  global = updateChat(global, chatId, {
-    topics: {
-      ...(chat.topics || {}),
-      [topicId]: updatedTopic,
-    },
-  });
-
-  global = updateThread(global, chatId, updatedTopic.id, {
-    firstMessageId: updatedTopic.id,
-  });
-
-  global = updateThreadInfo(global, chatId, updatedTopic.id, {
-    lastMessageId: updatedTopic.lastMessageId,
-    threadId: updatedTopic.id,
-    chatId,
-  });
-
-  return global;
-}
-
-export function deleteTopic<T extends GlobalState>(
-  global: T, chatId: string, topicId: number,
-) {
-  const chat = selectChat(global, chatId);
-  const topics = chat?.topics || {};
-  global = updateChat(global, chatId, {
-    topics: omit(topics, [topicId]),
-  });
-
-  return global;
-}
-
 export function addSimilarChannels<T extends GlobalState>(
   global: T,
   chatId: string,
diff --git a/src/global/reducers/index.ts b/src/global/reducers/index.ts
index c48c7d4ff..3ed9c26fe 100644
--- a/src/global/reducers/index.ts
+++ b/src/global/reducers/index.ts
@@ -14,3 +14,4 @@ export * from './stories';
 export * from './translations';
 export * from './peers';
 export * from './password';
+export * from './topics';
diff --git a/src/global/reducers/messages.ts b/src/global/reducers/messages.ts
index 2ca529b1b..a99f7b1a1 100644
--- a/src/global/reducers/messages.ts
+++ b/src/global/reducers/messages.ts
@@ -21,7 +21,6 @@ import {
   mergeIdRanges, orderHistoryIds, orderPinnedIds,
 } from '../helpers';
 import {
-  selectChat,
   selectChatMessage,
   selectChatMessages,
   selectChatScheduledMessages,
@@ -43,10 +42,7 @@ import { removeIdFromSearchResults } from './middleSearch';
 import { updateTabState } from './tabs';
 import { clearMessageTranslation } from './translations';
 
-type MessageStoreSections = {
-  byId: Record<number, ApiMessage>;
-  threadsById: Record<number, Thread>;
-};
+type MessageStoreSections = GlobalState['messages']['byChatId'][string];
 
 export function updateCurrentMessageList<T extends GlobalState>(
   global: T,
@@ -128,7 +124,7 @@ export function updateThread<T extends GlobalState>(
   });
 }
 
-function updateMessageStore<T extends GlobalState>(
+export function updateMessageStore<T extends GlobalState>(
   global: T, chatId: string, update: Partial<MessageStoreSections>,
 ): T {
   const current = global.messages.byChatId[chatId] || { byId: {}, threadsById: {} };
@@ -823,32 +819,6 @@ export function updateThreadUnreadFromForwardedMessage<T extends GlobalState>(
   return global;
 }
 
-export function updateTopicLastMessageId<T extends GlobalState>(
-  global: T, chatId: string, threadId: ThreadId, lastMessageId: number,
-) {
-  const chat = selectChat(global, chatId);
-  if (!chat?.topics?.[threadId]) return global;
-  return {
-    ...global,
-    chats: {
-      ...global.chats,
-      byId: {
-        ...global.chats.byId,
-        [chatId]: {
-          ...chat,
-          topics: {
-            ...chat.topics,
-            [threadId]: {
-              ...chat.topics[threadId],
-              lastMessageId,
-            },
-          },
-        },
-      },
-    },
-  };
-}
-
 export function addActiveMediaDownload<T extends GlobalState>(
   global: T,
   mediaHash: string,
diff --git a/src/global/reducers/topics.ts b/src/global/reducers/topics.ts
new file mode 100644
index 000000000..21f8ede40
--- /dev/null
+++ b/src/global/reducers/topics.ts
@@ -0,0 +1,138 @@
+import type { ApiTopic } from '../../api/types';
+import type { GlobalState, TopicsInfo } from '../types';
+
+import { buildCollectionByKey, omit, unique } from '../../util/iteratees';
+import {
+  selectChat, selectTopic, selectTopics,
+  selectTopicsInfo,
+} from '../selectors';
+import { updateThread, updateThreadInfo } from './messages';
+
+function updateTopicsStore<T extends GlobalState>(
+  global: T, chatId: string, update: Partial<TopicsInfo>,
+) {
+  const info = global.chats.topicsInfoById[chatId] || {};
+
+  global = {
+    ...global,
+    chats: {
+      ...global.chats,
+      topicsInfoById: {
+        ...global.chats.topicsInfoById,
+        [chatId]: {
+          ...info,
+          ...update,
+        },
+      },
+    },
+  };
+
+  return global;
+}
+
+export function updateListedTopicIds<T extends GlobalState>(
+  global: T, chatId: string, topicIds: number[],
+): T {
+  const listedIds = selectTopicsInfo(global, chatId)?.listedTopicIds || [];
+  return updateTopicsStore(global, chatId, {
+    listedTopicIds: unique([
+      ...listedIds,
+      ...topicIds,
+    ]),
+  });
+}
+
+export function updateTopics<T extends GlobalState>(
+  global: T, chatId: string, topicsCount: number, topics: ApiTopic[],
+): T {
+  const oldTopics = selectTopics(global, chatId);
+  const newTopics = buildCollectionByKey(topics, 'id');
+
+  global = updateTopicsStore(global, chatId, {
+    topicsById: {
+      ...oldTopics,
+      ...newTopics,
+    },
+    totalCount: topicsCount,
+  });
+
+  topics.forEach((topic) => {
+    global = updateThread(global, chatId, topic.id, {
+      firstMessageId: topic.id,
+    });
+
+    global = updateThreadInfo(global, chatId, topic.id, {
+      lastMessageId: topic.lastMessageId,
+      threadId: topic.id,
+      chatId,
+    });
+  });
+
+  return global;
+}
+
+export function updateTopic<T extends GlobalState>(
+  global: T, chatId: string, topicId: number, update: Partial<ApiTopic>,
+): T {
+  const chat = selectChat(global, chatId);
+
+  if (!chat) return global;
+
+  const topic = selectTopic(global, chatId, topicId);
+  const oldTopics = selectTopics(global, chatId);
+
+  const updatedTopic = {
+    ...topic,
+    ...update,
+  } as ApiTopic;
+
+  if (!updatedTopic.id) return global;
+
+  global = updateTopicsStore(global, chatId, {
+    topicsById: {
+      ...oldTopics,
+      [topicId]: updatedTopic,
+    },
+  });
+
+  global = updateThread(global, chatId, updatedTopic.id, {
+    firstMessageId: updatedTopic.id,
+  });
+
+  global = updateThreadInfo(global, chatId, updatedTopic.id, {
+    lastMessageId: updatedTopic.lastMessageId,
+    threadId: updatedTopic.id,
+    chatId,
+  });
+
+  return global;
+}
+
+export function deleteTopic<T extends GlobalState>(
+  global: T, chatId: string, topicId: number,
+) {
+  const topics = selectTopics(global, chatId);
+  if (!topics) return global;
+
+  global = updateTopicsStore(global, chatId, {
+    topicsById: omit(topics, [topicId]),
+  });
+
+  return global;
+}
+
+export function updateTopicLastMessageId<T extends GlobalState>(
+  global: T, chatId: string, threadId: number, lastMessageId: number,
+) {
+  return updateTopic(global, chatId, threadId, {
+    lastMessageId,
+  });
+}
+
+export function replacePinnedTopicIds<T extends GlobalState>(
+  global: T, chatId: string, pinnedTopicIds: number[],
+) {
+  return updateTopicsStore(global, chatId, {
+    orderedPinnedTopicIds: pinnedTopicIds,
+  });
+}
diff --git a/src/global/selectors/index.ts b/src/global/selectors/index.ts
index 469d88b7d..3281775a8 100644
--- a/src/global/selectors/index.ts
+++ b/src/global/selectors/index.ts
@@ -12,3 +12,4 @@ export * from './statistics';
 export * from './stories';
 export * from './tabs';
 export * from './peers';
+export * from './topics';
diff --git a/src/global/selectors/messages.ts b/src/global/selectors/messages.ts
index 5485efb51..e9897af4d 100644
--- a/src/global/selectors/messages.ts
+++ b/src/global/selectors/messages.ts
@@ -70,6 +70,7 @@ import { selectPeer } from './peers';
 import { selectPeerStory } from './stories';
 import { selectIsStickerFavorite } from './symbols';
 import { selectTabState } from './tabs';
+import { selectTopic } from './topics';
 import {
   selectBot, selectIsCurrentUserPremium, selectUser, selectUserStatus,
 } from './users';
@@ -483,17 +484,21 @@ export function selectForwardedSender<T extends GlobalState>(
   return undefined;
 }
 
+export function selectTopicFromMessage<T extends GlobalState>(global: T, message: ApiMessage) {
+  const { chatId } = message;
+  const chat = selectChat(global, chatId);
+  if (!chat?.isForum) return undefined;
+
+  const threadId = selectThreadIdFromMessage(global, message);
+  return selectTopic(global, chatId, threadId);
+}
+
 const MAX_MESSAGES_TO_DELETE_OWNER_TOPIC = 10;
 export function selectCanDeleteOwnerTopic<T extends GlobalState>(global: T, chatId: string, topicId: number) {
-  const chat = selectChat(global, chatId);
-  if (!chat) {
-    return false;
-  }
-
-  if (chat.topics?.[topicId] && !chat.topics?.[topicId].isOwner) return false;
-
-  const thread = global.messages.byChatId[chatId]?.threadsById[topicId];
+  const topic = selectTopic(global, chatId, topicId);
+  if (topic && !topic.isOwner) return false;
 
+  const thread = selectThread(global, chatId, topicId);
   if (!thread) return false;
 
   const { listedIds } = thread;
@@ -576,15 +581,6 @@ export function selectThreadIdFromMessage<T extends GlobalState>(global: T, mess
   return replyToTopId || replyToMsgId || GENERAL_TOPIC_ID;
 }
 
-export function selectTopicFromMessage<T extends GlobalState>(global: T, message: ApiMessage) {
-  const { chatId } = message;
-  const chat = selectChat(global, chatId);
-  if (!chat?.isForum) return undefined;
-
-  const threadId = selectThreadIdFromMessage(global, message);
-  return chat.topics?.[threadId];
-}
-
 export function selectCanReplyToMessage<T extends GlobalState>(global: T, message: ApiMessage, threadId: ThreadId) {
   const chat = selectChat(global, message.chatId);
   if (!chat || chat.isRestricted || chat.isForbidden) return false;
@@ -597,7 +593,8 @@ export function selectCanReplyToMessage<T extends GlobalState>(global: T, messag
   const threadInfo = selectThreadInfo(global, message.chatId, threadId);
   const isMessageThread = Boolean(!threadInfo?.isCommentsInfo && threadInfo?.fromChannelId);
   const chatFullInfo = selectChatFullInfo(global, chat.id);
-  const canPostInChat = getCanPostInChat(chat, threadId, isMessageThread, chatFullInfo);
+  const topic = selectTopic(global, chat.id, threadId);
+  const canPostInChat = getCanPostInChat(chat, topic, isMessageThread, chatFullInfo);
   if (!canPostInChat) return false;
 
   const messageTopic = selectTopicFromMessage(global, message);
diff --git a/src/global/selectors/topics.ts b/src/global/selectors/topics.ts
new file mode 100644
index 000000000..0b8ec77a2
--- /dev/null
+++ b/src/global/selectors/topics.ts
@@ -0,0 +1,14 @@
+import type { ThreadId } from '../../types';
+import type { GlobalState, TopicsInfo } from '../types';
+
+export function selectTopicsInfo<T extends GlobalState>(global: T, chatId: string): TopicsInfo | undefined {
+  return global.chats.topicsInfoById[chatId];
+}
+
+export function selectTopics<T extends GlobalState>(global: T, chatId: string) {
+  return selectTopicsInfo(global, chatId)?.topicsById;
+}
+
+export function selectTopic<T extends GlobalState>(global: T, chatId: string, threadId: ThreadId) {
+  return selectTopicsInfo(global, chatId)?.topicsById?.[threadId];
+}
diff --git a/src/global/types.ts b/src/global/types.ts
index 991c2d761..b9fc53b90 100644
--- a/src/global/types.ts
+++ b/src/global/types.ts
@@ -74,6 +74,7 @@ import type {
   ApiThemeParameters,
   ApiThreadInfo,
   ApiTimezone,
+  ApiTopic,
   ApiTranscription,
   ApiTypeStoryView,
   ApiTypingStatus,
@@ -213,6 +214,13 @@ export interface ServiceNotification {
   isDeleted?: boolean;
 }
 
+export interface TopicsInfo {
+  totalCount: number;
+  topicsById: Record<ThreadId, ApiTopic>;
+  listedTopicIds?: number[];
+  orderedPinnedTopicIds?: number[];
+}
+
 export type ApiLimitType =
   | 'uploadMaxFileparts'
   | 'stickersFaved'
@@ -968,6 +976,7 @@ export type GlobalState = {
       all?: Record<string, number>;
       saved?: Record<string, number>;
     };
+    topicsInfoById: Record<string, TopicsInfo>;
     loadingParameters: Record<ChatListType, {
       nextOffsetId?: number;
       nextOffsetPeerId?: string;
diff --git a/src/util/folderManager.ts b/src/util/folderManager.ts
index 5c3f49ede..366b3c338 100644
--- a/src/util/folderManager.ts
+++ b/src/util/folderManager.ts
@@ -18,6 +18,7 @@ import {
   selectNotifyExceptions,
   selectNotifySettings,
   selectTabState,
+  selectTopics,
 } from '../global/selectors';
 import arePropsShallowEqual from './arePropsShallowEqual';
 import { createCallbackManager } from './callbacks';
@@ -74,6 +75,7 @@ let prevGlobal: {
   isSavedFolderFullyLoaded?: boolean;
   lastAllMessageIds?: GlobalState['chats']['lastMessageIds']['all'];
   lastSavedMessageIds?: GlobalState['chats']['lastMessageIds']['saved'];
+  topicsInfoById: GlobalState['chats']['topicsInfoById'];
   chatsById: Record<string, ApiChat>;
   foldersById: Record<string, ApiChatFolder>;
   usersById: Record<string, ApiUser>;
@@ -215,6 +217,7 @@ function updateFolderManager(global: GlobalState) {
   const areChatsChanged = global.chats.byId !== prevGlobal.chatsById;
   const areSavedLastMessageIdsChanged = global.chats.lastMessageIds.saved !== prevGlobal.lastSavedMessageIds;
   const areAllLastMessageIdsChanged = global.chats.lastMessageIds.all !== prevGlobal.lastAllMessageIds;
+  const areTopicsChanged = global.chats.topicsInfoById !== prevGlobal.topicsInfoById;
   const areUsersChanged = global.users.byId !== prevGlobal.usersById;
   const areNotifySettingsChanged = selectNotifySettings(global) !== prevGlobal.notifySettings;
   const areNotifyExceptionsChanged = selectNotifyExceptions(global) !== prevGlobal.notifyExceptions;
@@ -229,7 +232,7 @@ function updateFolderManager(global: GlobalState) {
 
   if (!(
     isAllFolderChanged || isArchivedFolderChanged || isSavedFolderChanged || areFoldersChanged
-    || areChatsChanged || areUsersChanged || areNotifySettingsChanged || areNotifyExceptionsChanged
+    || areChatsChanged || areUsersChanged || areTopicsChanged || areNotifySettingsChanged || areNotifyExceptionsChanged
     || areSavedLastMessageIdsChanged || areAllLastMessageIdsChanged
   )
   ) {
@@ -515,8 +518,9 @@ function buildChatSummary<T extends GlobalState>(
   const {
     id, type, isRestricted, isNotJoined, migratedTo, folderId,
     unreadCount: chatUnreadCount, unreadMentionsCount: chatUnreadMentionsCount, hasUnreadMark,
-    isForum, topics,
+    isForum,
   } = chat;
+  const topics = selectTopics(global, chat.id);
 
   const { unreadCount, unreadMentionsCount } = isForum
     ? Object.values(topics || {}).reduce((acc, topic) => {
@@ -805,6 +809,7 @@ function buildInitials() {
       foldersById: {},
       chatsById: {},
       usersById: {},
+      topicsInfoById: {},
       notifySettings: {} as NotifySettings,
       notifyExceptions: {},
     },