diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index 6881a762b..845ebde7f 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -1168,6 +1168,69 @@ void ApiWrap::requestPeer(not_null<PeerData*> peer) {
 	_peerRequests.insert(peer, requestId);
 }
 
+void ApiWrap::migrateChat(
+		not_null<ChatData*> chat,
+		FnMut<void(not_null<ChannelData*>)> done,
+		FnMut<void(const RPCError &)> fail) {
+	const auto callback = [&] {
+		return MigrateCallbacks{ std::move(done), std::move(fail) };
+	};
+	const auto i = _migrateCallbacks.find(chat);
+	if (i != end(_migrateCallbacks)) {
+		i->second.push_back(callback());
+		return;
+	} else if (const auto channel = chat->migrateTo()) {
+		Notify::peerUpdatedDelayed(
+			chat,
+			Notify::PeerUpdate::Flag::MigrationChanged);
+		crl::on_main([=, done = std::move(done)]() mutable {
+			Notify::peerUpdatedSendDelayed();
+			done(channel);
+		});
+	} else if (chat->isDeactivated()) {
+		crl::on_main([fail = std::move(fail)]() mutable {
+			fail(RPCError::Local(
+				"BAD_MIGRATION",
+				"Chat is already deactivated"));
+		});
+		return;
+	} else if (!chat->amCreator()) {
+		crl::on_main([fail = std::move(fail)]() mutable {
+			fail(RPCError::Local(
+				"BAD_MIGRATION",
+				"Current user is not the creator of that chat"));
+		});
+		return;
+	}
+
+	_migrateCallbacks.emplace(chat).first->second.push_back(callback());
+	request(MTPmessages_MigrateChat(
+		chat->inputChat
+	)).done([=](const MTPUpdates &result) {
+		applyUpdates(result);
+		Notify::peerUpdatedSendDelayed();
+
+		const auto channel = chat->migrateTo();
+		if (auto handlers = _migrateCallbacks.take(chat)) {
+			for (auto &handler : *handlers) {
+				if (channel) {
+					handler.done(channel);
+				} else {
+					handler.fail(RPCError::Local(
+						"MIGRATION_FAIL",
+						"No channel"));
+				}
+			}
+		}
+	}).fail([=](const RPCError &error) {
+		if (auto handlers = _migrateCallbacks.take(chat)) {
+			for (auto &handler : *handlers) {
+				handler.fail(error);
+			}
+		}
+	}).send();
+}
+
 void ApiWrap::markMediaRead(
 		const base::flat_set<not_null<HistoryItem*>> &items) {
 	auto markedIds = QVector<MTPint>();
diff --git a/Telegram/SourceFiles/apiwrap.h b/Telegram/SourceFiles/apiwrap.h
index b429994be..9341691a1 100644
--- a/Telegram/SourceFiles/apiwrap.h
+++ b/Telegram/SourceFiles/apiwrap.h
@@ -137,6 +137,11 @@ public:
 		not_null<UserData*> user,
 		const MTPUserFull &result);
 
+	void migrateChat(
+		not_null<ChatData*> chat,
+		FnMut<void(not_null<ChannelData*>)> done,
+		FnMut<void(const RPCError &)> fail = nullptr);
+
 	void markMediaRead(const base::flat_set<not_null<HistoryItem*>> &items);
 	void markMediaRead(not_null<HistoryItem*> item);
 
@@ -727,6 +732,14 @@ private:
 	FnMut<void(const MTPChatInvite &result)> _checkInviteDone;
 	FnMut<void(const RPCError &error)> _checkInviteFail;
 
+	struct MigrateCallbacks {
+		FnMut<void(not_null<ChannelData*>)> done;
+		FnMut<void(const RPCError&)> fail;
+	};
+	base::flat_map<
+		not_null<ChatData*>,
+		std::vector<MigrateCallbacks>> _migrateCallbacks;
+
 	std::vector<FnMut<void(const MTPUser &)>> _supportContactCallbacks;
 
 	base::flat_map<FullMsgId, not_null<PeerData*>> _peerPhotoUploads;
diff --git a/Telegram/SourceFiles/boxes/add_contact_box.cpp b/Telegram/SourceFiles/boxes/add_contact_box.cpp
index 774b650a7..ed4c71744 100644
--- a/Telegram/SourceFiles/boxes/add_contact_box.cpp
+++ b/Telegram/SourceFiles/boxes/add_contact_box.cpp
@@ -608,8 +608,7 @@ void GroupInfoBox::submit() {
 		};
 		Ui::show(
 			Box<PeerListBox>(
-				std::make_unique<AddParticipantsBoxController>(
-					nullptr),
+				std::make_unique<AddParticipantsBoxController>(),
 				std::move(initBox)),
 			LayerOption::KeepOther);
 	}
diff --git a/Telegram/SourceFiles/boxes/peer_list_box.cpp b/Telegram/SourceFiles/boxes/peer_list_box.cpp
index dc62d189a..64d4934e8 100644
--- a/Telegram/SourceFiles/boxes/peer_list_box.cpp
+++ b/Telegram/SourceFiles/boxes/peer_list_box.cpp
@@ -318,12 +318,15 @@ int PeerListBox::peerListSelectedRowsCount() {
 	return _select ? _select->entity()->getItemsCount() : 0;
 }
 
-std::vector<not_null<PeerData*>> PeerListBox::peerListCollectSelectedRows() {
-	auto result = std::vector<not_null<PeerData*>> {};
-	auto items = _select ? _select->entity()->getItems() : QVector<uint64> {};
+auto PeerListBox::peerListCollectSelectedRows()
+-> std::vector<not_null<PeerData*>> {
+	auto result = std::vector<not_null<PeerData*>>();
+	auto items = _select
+		? _select->entity()->getItems()
+		: QVector<uint64>();
 	if (!items.empty()) {
 		result.reserve(items.size());
-		for_const (auto itemId, items) {
+		for (const auto itemId : items) {
 			result.push_back(App::peer(itemId));
 		}
 	}
diff --git a/Telegram/SourceFiles/boxes/peer_list_box.h b/Telegram/SourceFiles/boxes/peer_list_box.h
index 04fa47de0..3cd9867ec 100644
--- a/Telegram/SourceFiles/boxes/peer_list_box.h
+++ b/Telegram/SourceFiles/boxes/peer_list_box.h
@@ -303,6 +303,10 @@ public:
 		std::unique_ptr<SavedStateBase> state) {
 	}
 
+	rpl::lifetime &lifetime() {
+		return _lifetime;
+	}
+
 protected:
 	not_null<PeerListSearchDelegate*> delegate() const {
 		return _delegate;
@@ -310,6 +314,7 @@ protected:
 
 private:
 	PeerListSearchDelegate *_delegate = nullptr;
+	rpl::lifetime _lifetime;
 
 };
 
@@ -320,7 +325,8 @@ public:
 	};
 
 	// Search works only with RowId == peer->id.
-	PeerListController(std::unique_ptr<PeerListSearchController> searchController = nullptr);
+	PeerListController(
+		std::unique_ptr<PeerListSearchController> searchController = {});
 
 	void setDelegate(not_null<PeerListDelegate*> delegate) {
 		_delegate = delegate;
diff --git a/Telegram/SourceFiles/boxes/peer_list_controllers.cpp b/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
index 76e08f1e6..2695a08c0 100644
--- a/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
+++ b/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
@@ -307,7 +307,9 @@ bool ChatsListBoxController::appendRow(not_null<History*> history) {
 	return false;
 }
 
-ContactsBoxController::ContactsBoxController(std::unique_ptr<PeerListSearchController> searchController) : PeerListController(std::move(searchController)) {
+ContactsBoxController::ContactsBoxController(
+	std::unique_ptr<PeerListSearchController> searchController)
+: PeerListController(std::move(searchController)) {
 }
 
 void ContactsBoxController::prepare() {
diff --git a/Telegram/SourceFiles/boxes/peer_list_controllers.h b/Telegram/SourceFiles/boxes/peer_list_controllers.h
index c0f7fd699..8a932bb46 100644
--- a/Telegram/SourceFiles/boxes/peer_list_controllers.h
+++ b/Telegram/SourceFiles/boxes/peer_list_controllers.h
@@ -114,9 +114,13 @@ private:
 
 };
 
-class ContactsBoxController : public PeerListController, protected base::Subscriber {
+class ContactsBoxController
+	: public PeerListController
+	, protected base::Subscriber {
 public:
-	ContactsBoxController(std::unique_ptr<PeerListSearchController> searchController = std::make_unique<PeerListGlobalSearchController>());
+	ContactsBoxController(
+		std::unique_ptr<PeerListSearchController> searchController
+		= std::make_unique<PeerListGlobalSearchController>());
 
 	void prepare() override final;
 	std::unique_ptr<PeerListRow> createSearchRow(not_null<PeerData*> peer) override final;
diff --git a/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp b/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
index eaa3c4226..1696e4e76 100644
--- a/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
@@ -40,61 +40,63 @@ base::flat_set<not_null<UserData*>> GetAlreadyInFromPeer(PeerData *peer) {
 	return {};
 }
 
-bool InviteSelectedUsers(
-		not_null<PeerListBox*> box,
-		not_null<PeerData*> chat) {
-	const auto rows = box->peerListCollectSelectedRows();
-	const auto users = ranges::view::all(
-		rows
-	) | ranges::view::transform([](not_null<PeerData*> peer) {
-		Expects(peer->isUser());
-		Expects(!peer->isSelf());
-
-		return not_null<UserData*>(peer->asUser());
-	}) | ranges::to_vector;
-	if (users.empty()) {
-		return false;
-	}
-	chat->session().api().addChatParticipants(chat, users);
-	return true;
-}
-
 } // namespace
 
-AddParticipantsBoxController::AddParticipantsBoxController(PeerData *peer)
-: ContactsBoxController(std::make_unique<PeerListGlobalSearchController>())
-, _peer(peer)
-, _alreadyIn(GetAlreadyInFromPeer(peer)) {
+AddParticipantsBoxController::AddParticipantsBoxController()
+: ContactsBoxController(
+	std::make_unique<PeerListGlobalSearchController>()) {
 }
 
 AddParticipantsBoxController::AddParticipantsBoxController(
-	not_null<ChannelData*> channel,
+	not_null<PeerData*> peer)
+: AddParticipantsBoxController(peer, GetAlreadyInFromPeer(peer)) {
+}
+
+AddParticipantsBoxController::AddParticipantsBoxController(
+	not_null<PeerData*> peer,
 	base::flat_set<not_null<UserData*>> &&alreadyIn)
 : ContactsBoxController(std::make_unique<PeerListGlobalSearchController>())
-, _peer(channel)
+, _peer(peer)
 , _alreadyIn(std::move(alreadyIn)) {
+	subscribeToMigration();
+}
+
+void AddParticipantsBoxController::subscribeToMigration() {
+	Expects(_peer != nullptr);
+
+	SubscribeToMigration(
+		_peer,
+		lifetime(),
+		[=](not_null<ChannelData*> channel) { _peer = channel; });
 }
 
 void AddParticipantsBoxController::rowClicked(not_null<PeerListRow*> row) {
 	auto count = fullCount();
-	auto limit = (_peer && _peer->isMegagroup()) ? Global::MegagroupSizeMax() : Global::ChatSizeMax();
+	auto limit = _peer && (_peer->isChat() || _peer->isMegagroup())
+		? Global::MegagroupSizeMax()
+		: Global::ChatSizeMax();
 	if (count < limit || row->checked()) {
 		delegate()->peerListSetRowChecked(row, !row->checked());
 		updateTitle();
-	} else if (auto channel = _peer ? _peer->asChannel() : nullptr) {
+	} else if (const auto channel = _peer ? _peer->asChannel() : nullptr) {
 		if (!_peer->isMegagroup()) {
 			Ui::show(
 				Box<MaxInviteBox>(_peer->asChannel()),
 				LayerOption::KeepOther);
 		}
-	} else if (count >= Global::ChatSizeMax() && count < Global::MegagroupSizeMax()) {
+	} else if (count >= Global::ChatSizeMax()
+		&& count < Global::MegagroupSizeMax()) {
+		// #TODO groups new error about "after creating"
 		Ui::show(
-			Box<InformBox>(lng_profile_add_more_after_upgrade(lt_count, Global::MegagroupSizeMax())),
+			Box<InformBox>(lng_profile_add_more_after_upgrade(
+				lt_count,
+				Global::MegagroupSizeMax())),
 			LayerOption::KeepOther);
 	}
 }
 
-void AddParticipantsBoxController::itemDeselectedHook(not_null<PeerData*> peer) {
+void AddParticipantsBoxController::itemDeselectedHook(
+		not_null<PeerData*> peer) {
 	updateTitle();
 }
 
@@ -106,23 +108,26 @@ int AddParticipantsBoxController::alreadyInCount() const {
 	if (!_peer) {
 		return 1; // self
 	}
-	if (auto chat = _peer->asChat()) {
+	if (const auto chat = _peer->asChat()) {
 		return qMax(chat->count, 1);
-	} else if (auto channel = _peer->asChannel()) {
+	} else if (const auto channel = _peer->asChannel()) {
 		return qMax(channel->membersCount(), int(_alreadyIn.size()));
 	}
 	Unexpected("User in AddParticipantsBoxController::alreadyInCount");
 }
 
-bool AddParticipantsBoxController::isAlreadyIn(not_null<UserData*> user) const {
+bool AddParticipantsBoxController::isAlreadyIn(
+		not_null<UserData*> user) const {
 	if (!_peer) {
 		return false;
 	}
-	if (auto chat = _peer->asChat()) {
-		return chat->participants.contains(user);
-	} else if (auto channel = _peer->asChannel()) {
+	if (const auto chat = _peer->asChat()) {
 		return _alreadyIn.contains(user)
-			|| (channel->isMegagroup() && base::contains(channel->mgInfo->lastParticipants, user));
+			|| chat->participants.contains(user);
+	} else if (const auto channel = _peer->asChannel()) {
+		return _alreadyIn.contains(user)
+			|| (channel->isMegagroup()
+				&& base::contains(channel->mgInfo->lastParticipants, user));
 	}
 	Unexpected("User in AddParticipantsBoxController::isAlreadyIn");
 }
@@ -144,25 +149,49 @@ std::unique_ptr<PeerListRow> AddParticipantsBoxController::createRow(
 }
 
 void AddParticipantsBoxController::updateTitle() {
-	auto additional = (_peer && _peer->isChannel() && !_peer->isMegagroup())
+	const auto additional = (_peer
+		&& _peer->isChannel()
+		&& !_peer->isMegagroup())
 		? QString() :
 		QString("%1 / %2").arg(fullCount()).arg(Global::MegagroupSizeMax());
 	delegate()->peerListSetTitle(langFactory(lng_profile_add_participant));
-	delegate()->peerListSetAdditionalTitle([additional] { return additional; });
+	delegate()->peerListSetAdditionalTitle([=] { return additional; });
+}
+
+bool AddParticipantsBoxController::inviteSelectedUsers(
+		not_null<PeerListBox*> box) const {
+	Expects(_peer != nullptr);
+
+	const auto rows = box->peerListCollectSelectedRows();
+	const auto users = ranges::view::all(
+		rows
+	) | ranges::view::transform([](not_null<PeerData*> peer) {
+		Expects(peer->isUser());
+		Expects(!peer->isSelf());
+
+		return not_null<UserData*>(peer->asUser());
+	}) | ranges::to_vector;
+	if (users.empty()) {
+		return false;
+	}
+	_peer->session().api().addChatParticipants(_peer, users);
+	return true;
 }
 
 void AddParticipantsBoxController::Start(not_null<ChatData*> chat) {
+	auto controller = std::make_unique<AddParticipantsBoxController>(chat);
+	const auto weak = controller.get();
 	auto initBox = [=](not_null<PeerListBox*> box) {
 		box->addButton(langFactory(lng_participant_invite), [=] {
-			if (InviteSelectedUsers(box, chat)) {
+			if (weak->inviteSelectedUsers(box)) {
 				Ui::showPeerHistory(chat, ShowAtTheEndMsgId);
 			}
 		});
-		box->addButton(langFactory(lng_cancel), [box] { box->closeBox(); });
+		box->addButton(langFactory(lng_cancel), [=] { box->closeBox(); });
 	};
 	Ui::show(
 		Box<PeerListBox>(
-			std::make_unique<AddParticipantsBoxController>(chat),
+			std::move(controller),
 			std::move(initBox)),
 		LayerOption::KeepOther);
 }
@@ -171,10 +200,13 @@ void AddParticipantsBoxController::Start(
 		not_null<ChannelData*> channel,
 		base::flat_set<not_null<UserData*>> &&alreadyIn,
 		bool justCreated) {
-	auto initBox = [channel, justCreated](not_null<PeerListBox*> box) {
-		auto subscription = std::make_shared<rpl::lifetime>();
-		box->addButton(langFactory(lng_participant_invite), [=, copy = subscription] {
-			if (InviteSelectedUsers(box, channel)) {
+	auto controller = std::make_unique<AddParticipantsBoxController>(
+		channel,
+		std::move(alreadyIn));
+	const auto weak = controller.get();
+	auto initBox = [=](not_null<PeerListBox*> box) {
+		box->addButton(langFactory(lng_participant_invite), [=] {
+			if (weak->inviteSelectedUsers(box)) {
 				if (channel->isMegagroup()) {
 					Ui::showPeerHistory(channel, ShowAtTheEndMsgId);
 				} else {
@@ -182,18 +214,18 @@ void AddParticipantsBoxController::Start(
 				}
 			}
 		});
-		box->addButton(langFactory(justCreated ? lng_create_group_skip : lng_cancel), [box] { box->closeBox(); });
+		box->addButton(
+			langFactory(justCreated ? lng_create_group_skip : lng_cancel),
+			[=] { box->closeBox(); });
 		if (justCreated) {
 			box->boxClosing() | rpl::start_with_next([=] {
 				Ui::showPeerHistory(channel, ShowAtTheEndMsgId);
-			}, *subscription);
+			}, box->lifetime());
 		}
 	};
 	Ui::show(
 		Box<PeerListBox>(
-			std::make_unique<AddParticipantsBoxController>(
-				channel,
-				std::move(alreadyIn)),
+			std::move(controller),
 			std::move(initBox)),
 		LayerOption::KeepOther);
 }
@@ -221,9 +253,23 @@ AddSpecialBoxController::AddSpecialBoxController(
 , _additional(peer, Role::Members)
 , _adminDoneCallback(std::move(adminDoneCallback))
 , _bannedDoneCallback(std::move(bannedDoneCallback)) {
+	subscribeToMigration();
 }
 
-std::unique_ptr<PeerListRow> AddSpecialBoxController::createSearchRow(not_null<PeerData*> peer) {
+void AddSpecialBoxController::subscribeToMigration() {
+	SubscribeToMigration(
+		_peer,
+		lifetime(),
+		[=](not_null<ChannelData*> channel) { migrate(channel); });
+}
+
+void AddSpecialBoxController::migrate(not_null<ChannelData*> channel) {
+	_peer = channel;
+	_additional.migrate(channel);
+}
+
+std::unique_ptr<PeerListRow> AddSpecialBoxController::createSearchRow(
+		not_null<PeerData*> peer) {
 	if (peer->isSelf()) {
 		return nullptr;
 	}
@@ -237,9 +283,12 @@ void AddSpecialBoxController::prepare() {
 	delegate()->peerListSetSearchMode(PeerListSearchMode::Enabled);
 	const auto title = [&] {
 		switch (_role) {
-		case Role::Admins: return langFactory(lng_channel_add_admin);
-		case Role::Restricted: return langFactory(lng_channel_add_restricted);
-		case Role::Kicked: return langFactory(lng_channel_add_banned);
+		case Role::Admins:
+			return langFactory(lng_channel_add_admin);
+		case Role::Restricted:
+			return langFactory(lng_channel_add_restricted);
+		case Role::Kicked:
+			return langFactory(lng_channel_add_banned);
 		}
 		Unexpected("Role in AddSpecialBoxController::prepare()");
 	}();
@@ -723,6 +772,14 @@ AddSpecialBoxSearchController::AddSpecialBoxSearchController(
 : _peer(peer)
 , _additional(additional)
 , _timer([=] { searchOnServer(); }) {
+	subscribeToMigration();
+}
+
+void AddSpecialBoxSearchController::subscribeToMigration() {
+	SubscribeToMigration(
+		_peer,
+		lifetime(),
+		[=](not_null<ChannelData*> channel) { _peer = channel; });
 }
 
 void AddSpecialBoxSearchController::searchQuery(const QString &query) {
@@ -752,10 +809,13 @@ bool AddSpecialBoxSearchController::isLoading() {
 }
 
 bool AddSpecialBoxSearchController::searchParticipantsInCache() {
-	auto it = _participantsCache.find(_query);
-	if (it != _participantsCache.cend()) {
+	const auto i = _participantsCache.find(_query);
+	if (i != _participantsCache.cend()) {
 		_requestId = 0;
-		searchParticipantsDone(_requestId, it->second.result, it->second.requestedCount);
+		searchParticipantsDone(
+			_requestId,
+			i->second.result,
+			i->second.requestedCount);
 		return true;
 	}
 	return false;
@@ -837,8 +897,7 @@ void AddSpecialBoxSearchController::searchParticipantsDone(
 	const auto channel = _peer->asChannel();
 	auto query = _query;
 	if (requestId) {
-		auto &session = channel->session();
-		session.api().parseChannelParticipants(channel, result, [&](auto&&...) {
+		const auto addToCache = [&](auto&&...) {
 			auto it = _participantsQueries.find(requestId);
 			if (it != _participantsQueries.cend()) {
 				query = it->second.text;
@@ -849,7 +908,11 @@ void AddSpecialBoxSearchController::searchParticipantsDone(
 				}
 				_participantsQueries.erase(it);
 			}
-		});
+		};
+		channel->session().api().parseChannelParticipants(
+			channel,
+			result,
+			addToCache);
 	}
 
 	if (_requestId != requestId) {
@@ -857,14 +920,14 @@ void AddSpecialBoxSearchController::searchParticipantsDone(
 	}
 	_requestId = 0;
 	result.match([&](const MTPDchannels_channelParticipants &data) {
-		auto &list = data.vparticipants.v;
+		const auto &list = data.vparticipants.v;
 		if (list.size() < requestedCount) {
-			// We want cache to have full information about a query with small
-			// results count (if we don't need the second request). So we don't
-			// wait for an empty results list unlike the non-search peer list.
+			// We want cache to have full information about a query with
+			// small results count (that we don't need the second request).
+			// So we don't wait for empty list unlike the non-search case.
 			_participantsLoaded = true;
 			if (list.empty() && _offset == 0) {
-				// No results, so we want to request global search immediately.
+				// No results, request global search immediately.
 				loadMoreRows();
 			}
 		}
@@ -946,7 +1009,6 @@ void AddSpecialBoxSearchController::addChatMembers(
 	if (chat->participants.empty()) {
 		return;
 	}
-	_participantsLoaded = true;
 
 	const auto wordList = TextUtilities::PrepareSearchWords(_query);
 	if (wordList.empty()) {
@@ -1024,7 +1086,8 @@ void AddSpecialBoxSearchController::addChatsContacts() {
 		return result;
 	};
 	const auto dialogsIndex = getSmallestIndex(App::main()->dialogsList());
-	const auto contactsIndex = getSmallestIndex(App::main()->contactsNoDialogsList());
+	const auto contactsIndex = getSmallestIndex(
+		App::main()->contactsNoDialogsList());
 
 	const auto filterAndAppend = [&](const Dialogs::List *list) {
 		if (!list) {
diff --git a/Telegram/SourceFiles/boxes/peers/add_participants_box.h b/Telegram/SourceFiles/boxes/peers/add_participants_box.h
index ac4a95a5d..1eac6897b 100644
--- a/Telegram/SourceFiles/boxes/peers/add_participants_box.h
+++ b/Telegram/SourceFiles/boxes/peers/add_participants_box.h
@@ -18,9 +18,10 @@ public:
 		not_null<ChannelData*> channel,
 		base::flat_set<not_null<UserData*>> &&alreadyIn);
 
-	AddParticipantsBoxController(PeerData *peer);
+	AddParticipantsBoxController();
+	AddParticipantsBoxController(not_null<PeerData*> peer);
 	AddParticipantsBoxController(
-		not_null<ChannelData*> channel,
+		not_null<PeerData*> peer,
 		base::flat_set<not_null<UserData*>> &&alreadyIn);
 
 	using ContactsBoxController::ContactsBoxController;
@@ -39,11 +40,12 @@ private:
 		base::flat_set<not_null<UserData*>> &&alreadyIn,
 		bool justCreated);
 
+	bool inviteSelectedUsers(not_null<PeerListBox*> box) const;
+	void subscribeToMigration();
 	int alreadyInCount() const;
 	bool isAlreadyIn(not_null<UserData*> user) const;
 	int fullCount() const;
 	void updateTitle();
-	bool inviteSelectedUsers(not_null<PeerData*> chat) const;
 
 	PeerData *_peer = nullptr;
 	base::flat_set<not_null<UserData*>> _alreadyIn;
@@ -103,6 +105,9 @@ private:
 	bool prependRow(not_null<UserData*> user);
 	std::unique_ptr<PeerListRow> createRow(not_null<UserData*> user) const;
 
+	void subscribeToMigration();
+	void migrate(not_null<ChannelData*> channel);
+
 	not_null<PeerData*> _peer;
 	Role _role = Role::Admins;
 	int _offset = 0;
@@ -119,7 +124,8 @@ private:
 // Finds chat/channel members, then contacts, then global search results.
 class AddSpecialBoxSearchController
 	: public PeerListSearchController
-	, private MTP::Sender {
+	, private MTP::Sender
+	, private base::Subscriber {
 public:
 	using Role = ParticipantsBoxController::Role;
 
@@ -156,6 +162,8 @@ private:
 	void addChatsContacts();
 	void requestGlobal();
 
+	void subscribeToMigration();
+
 	not_null<PeerData*> _peer;
 	not_null<ParticipantsAdditionalData*> _additional;
 
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
index aa7014271..1382b5518 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
@@ -142,7 +142,16 @@ Fn<void(
 			const MTPChatAdminRights &oldRights,
 			const MTPChatAdminRights &newRights) {
 		const auto done = [=] { onDone(newRights); };
-		if (const auto chat = peer->asChat()) {
+		const auto saveForChannel = [=](not_null<ChannelData*> channel) {
+			SaveChannelAdmin(
+				channel,
+				user,
+				oldRights,
+				newRights,
+				done,
+				onFail);
+		};
+		if (const auto chat = peer->asChatNotMigrated()) {
 			const auto saveChatAdmin = [&](bool isAdmin) {
 				SaveChatAdmin(chat, user, isAdmin, done, onFail);
 			};
@@ -155,16 +164,10 @@ Fn<void(
 			} else if (!flags) {
 				saveChatAdmin(false);
 			} else {
-				// #TODO groups autoconv
+				peer->session().api().migrateChat(chat, saveForChannel);
 			}
-		} else if (const auto channel = peer->asChannel()) {
-			SaveChannelAdmin(
-				channel,
-				user,
-				oldRights,
-				newRights,
-				done,
-				onFail);
+		} else if (const auto channel = peer->asChannelOrMigrated()) {
+			saveForChannel(channel);
 		} else {
 			Unexpected("Peer in SaveAdminCallback.");
 		}
@@ -182,17 +185,7 @@ Fn<void(
 			const MTPChatBannedRights &oldRights,
 			const MTPChatBannedRights &newRights) {
 		const auto done = [=] { onDone(newRights); };
-		if (const auto chat = peer->asChat()) {
-			const auto flags = newRights.match([](
-					const MTPDchatBannedRights &data) {
-				return data.vflags.v;
-			});
-			if (!flags) {
-				done();
-			} else {
-				// #TODO groups autoconv
-			}
-		} else if (const auto channel = peer->asChannel()) {
+		const auto saveForChannel = [=](not_null<ChannelData*> channel) {
 			SaveChannelRestriction(
 				channel,
 				user,
@@ -200,12 +193,51 @@ Fn<void(
 				newRights,
 				done,
 				onFail);
+		};
+		if (const auto chat = peer->asChatNotMigrated()) {
+			const auto flags = newRights.match([](
+					const MTPDchatBannedRights &data) {
+				return data.vflags.v;
+			});
+			if (!flags) {
+				done();
+			} else {
+				peer->session().api().migrateChat(chat, saveForChannel);
+			}
+		} else if (const auto channel = peer->asChannelOrMigrated()) {
+			saveForChannel(channel);
 		} else {
 			Unexpected("Peer in SaveAdminCallback.");
 		}
 	};
 }
 
+void SubscribeToMigration(
+		not_null<PeerData*> peer,
+		rpl::lifetime &lifetime,
+		Fn<void(not_null<ChannelData*>)> migrate) {
+	if (const auto chat = peer->asChat()) {
+		if (const auto channel = peer->migrateTo()) {
+			migrate(channel);
+		} else if (!chat->isDeactivated()) {
+			const auto alive = lifetime.make_state<base::Subscription>();
+			const auto handler = [=](const Notify::PeerUpdate &update) {
+				if (update.peer == peer) {
+					if (const auto channel = peer->migrateTo()) {
+						const auto onstack = base::duplicate(migrate);
+						*alive = base::Subscription();
+						onstack(channel);
+					}
+				}
+			};
+			*alive = Notify::PeerUpdated().add_subscription(
+				Notify::PeerUpdatedHandler(
+					Notify::PeerUpdate::Flag::MigrationChanged,
+					handler));
+		}
+	}
+}
+
 ParticipantsAdditionalData::ParticipantsAdditionalData(
 	not_null<PeerData*> peer,
 	Role role)
@@ -214,7 +246,8 @@ ParticipantsAdditionalData::ParticipantsAdditionalData(
 	fillFromPeer();
 }
 
-bool ParticipantsAdditionalData::infoLoaded(not_null<UserData*> user) const {
+bool ParticipantsAdditionalData::infoLoaded(
+		not_null<UserData*> user) const {
 	return _peer->isChat()
 		|| (_infoNotLoaded.find(user) == end(_infoNotLoaded));
 }
@@ -286,7 +319,8 @@ bool ParticipantsAdditionalData::isCreator(not_null<UserData*> user) const {
 	return (_creator == user);
 }
 
-bool ParticipantsAdditionalData::isExternal(not_null<UserData*> user) const {
+bool ParticipantsAdditionalData::isExternal(
+		not_null<UserData*> user) const {
 	return _peer->isChat()
 		? !_members.contains(user)
 		: _external.find(user) != end(_external);
@@ -531,6 +565,23 @@ UserData *ParticipantsAdditionalData::applyBanned(
 	return user;
 }
 
+void ParticipantsAdditionalData::migrate(not_null<ChannelData*> channel) {
+	_peer = channel;
+	fillFromChannel(channel);
+
+	for (const auto user : _admins) {
+		_adminRights.emplace(
+			user,
+			MTP_chatAdminRights(MTP_flags(ChatData::DefaultAdminRights())));
+		if (channel->amCreator()) {
+			_adminCanEdit.emplace(user);
+		}
+		if (_creator) {
+			_adminPromotedBy.emplace(user, _creator);
+		}
+	}
+}
+
 ParticipantsOnlineSorter::ParticipantsOnlineSorter(
 	not_null<PeerData*> peer,
 	not_null<PeerListDelegate*> delegate)
@@ -608,6 +659,7 @@ ParticipantsBoxController::ParticipantsBoxController(
 , _peer(peer)
 , _role(role)
 , _additional(peer, _role) {
+	subscribeToMigration();
 	if (_role == Role::Profile) {
 		setupListChangeViewers();
 	}
@@ -1183,13 +1235,14 @@ bool ParticipantsBoxController::feedMegagroupLastParticipants() {
 	}
 	const auto info = megagroup->mgInfo.get();
 	//
-	// channelFull and channels_channelParticipants members count is desynced
+	// channelFull and channels_channelParticipants members count desynced
 	// so we almost always have LastParticipantsCountOutdated that is set
 	// inside setMembersCount() and so we almost never use lastParticipants.
 	//
 	// => disable this check temporarily.
 	//
-	//if (info->lastParticipantsStatus != MegagroupInfo::LastParticipantsUpToDate) {
+	//if (info->lastParticipantsStatus
+	//	!= MegagroupInfo::LastParticipantsUpToDate) {
 	//	_channel->updateFull();
 	//	return false;
 	//}
@@ -1227,7 +1280,8 @@ void ParticipantsBoxController::rowClicked(not_null<PeerListRow*> row) {
 	}
 }
 
-void ParticipantsBoxController::rowActionClicked(not_null<PeerListRow*> row) {
+void ParticipantsBoxController::rowActionClicked(
+		not_null<PeerListRow*> row) {
 	Expects(row->peer()->isUser());
 
 	const auto user = row->peer()->asUser();
@@ -1599,7 +1653,8 @@ void ParticipantsBoxController::recomputeTypeFor(
 	}
 }
 
-void ParticipantsBoxController::refreshCustomStatus(not_null<PeerListRow*> row) const {
+void ParticipantsBoxController::refreshCustomStatus(
+		not_null<PeerListRow*> row) const {
 	const auto user = row->peer()->asUser();
 	if (_role == Role::Admins) {
 		if (const auto by = _additional.adminPromotedBy(user)) {
@@ -1623,6 +1678,18 @@ void ParticipantsBoxController::refreshCustomStatus(not_null<PeerListRow*> row)
 	}
 }
 
+void ParticipantsBoxController::subscribeToMigration() {
+	SubscribeToMigration(
+		_peer,
+		lifetime(),
+		[=](not_null<ChannelData*> channel) { migrate(channel); });
+}
+
+void ParticipantsBoxController::migrate(not_null<ChannelData*> channel) {
+	_peer = channel;
+	_additional.migrate(channel);
+}
+
 ParticipantsBoxSearchController::ParticipantsBoxSearchController(
 	not_null<ChannelData*> channel,
 	Role role,
@@ -1686,10 +1753,13 @@ bool ParticipantsBoxSearchController::isLoading() {
 }
 
 bool ParticipantsBoxSearchController::searchInCache() {
-	auto it = _cache.find(_query);
-	if (it != _cache.cend()) {
+	const auto i = _cache.find(_query);
+	if (i != _cache.cend()) {
 		_requestId = 0;
-		searchDone(_requestId, it->second.result, it->second.requestedCount);
+		searchDone(
+			_requestId,
+			i->second.result,
+			i->second.requestedCount);
 		return true;
 	}
 	return false;
@@ -1706,11 +1776,14 @@ bool ParticipantsBoxSearchController::loadMoreRows() {
 		switch (_role) {
 		case Role::Admins: // Search for members, appoint as admin on found.
 		case Role::Profile:
-		case Role::Members: return MTP_channelParticipantsSearch(MTP_string(_query));
-		case Role::Restricted: return MTP_channelParticipantsBanned(MTP_string(_query));
-		case Role::Kicked: return MTP_channelParticipantsKicked(MTP_string(_query));
+		case Role::Members:
+			return MTP_channelParticipantsSearch(MTP_string(_query));
+		case Role::Restricted:
+			return MTP_channelParticipantsBanned(MTP_string(_query));
+		case Role::Kicked:
+			return MTP_channelParticipantsKicked(MTP_string(_query));
 		}
-		Unexpected("Role in ParticipantsBoxSearchController::loadMoreRows()");
+		Unexpected("Role in ParticipantsBoxSearchController.");
 	}();
 
 	// For search we request a lot of rows from the first query.
@@ -1725,9 +1798,11 @@ bool ParticipantsBoxSearchController::loadMoreRows() {
 		MTP_int(_offset),
 		MTP_int(perPage),
 		MTP_int(participantsHash)
-	)).done([this, perPage](const MTPchannels_ChannelParticipants &result, mtpRequestId requestId) {
+	)).done([=](
+			const MTPchannels_ChannelParticipants &result,
+			mtpRequestId requestId) {
 		searchDone(requestId, result, perPage);
-	}).fail([this](const RPCError &error, mtpRequestId requestId) {
+	}).fail([=](const RPCError &error, mtpRequestId requestId) {
 		if (_requestId == requestId) {
 			_requestId = 0;
 			_allLoaded = true;
@@ -1748,7 +1823,7 @@ void ParticipantsBoxSearchController::searchDone(
 		int requestedCount) {
 	auto query = _query;
 	if (requestId) {
-		_channel->session().api().parseChannelParticipants(_channel, result, [&](auto&&...) {
+		const auto addToCache = [&](auto&&...) {
 			auto it = _queries.find(requestId);
 			if (it != _queries.cend()) {
 				query = it->second.text;
@@ -1759,20 +1834,23 @@ void ParticipantsBoxSearchController::searchDone(
 				}
 				_queries.erase(it);
 			}
-		});
+		};
+		_channel->session().api().parseChannelParticipants(
+			_channel,
+			result,
+			addToCache);
 	}
-
 	if (_requestId != requestId) {
 		return;
 	}
 
 	_requestId = 0;
 	result.match([&](const MTPDchannels_channelParticipants &data) {
-		auto &list = data.vparticipants.v;
+		const auto &list = data.vparticipants.v;
 		if (list.size() < requestedCount) {
-			// We want cache to have full information about a query with small
-			// results count (if we don't need the second request). So we don't
-			// wait for an empty results list unlike the non-search peer list.
+			// We want cache to have full information about a query with
+			// small results count (that we don't need the second request).
+			// So we don't wait for empty list unlike the non-search case.
 			_allLoaded = true;
 		}
 		const auto overrideRole = (_role == Role::Admins)
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participants_box.h b/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
index 38c3c69e9..58e16fa6c 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
+++ b/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
@@ -36,6 +36,11 @@ Fn<void(
 		Fn<void(const MTPChatBannedRights &newRights)> onDone,
 		Fn<void()> onFail);
 
+void SubscribeToMigration(
+	not_null<PeerData*> peer,
+	rpl::lifetime &lifetime,
+	Fn<void(not_null<ChannelData*>)> migrate);
+
 enum class ParticipantsRole {
 	Profile,
 	Members,
@@ -92,6 +97,8 @@ public:
 	[[nodiscard]] UserData *adminPromotedBy(not_null<UserData*> user) const;
 	[[nodiscard]] UserData *restrictedBy(not_null<UserData*> user) const;
 
+	void migrate(not_null<ChannelData*> channel);
+
 private:
 	UserData *applyCreator(const MTPDchannelParticipantCreator &data);
 	UserData *applyAdmin(const MTPDchannelParticipantAdmin &data);
@@ -216,6 +223,9 @@ private:
 	Type computeType(not_null<UserData*> user) const;
 	void recomputeTypeFor(not_null<UserData*> user);
 
+	void subscribeToMigration();
+	void migrate(not_null<ChannelData*> channel);
+
 	not_null<Window::Navigation*> _navigation;
 	not_null<PeerData*> _peer;
 	Role _role = Role::Admins;
diff --git a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
index aab3cebee..33a6c70b9 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
@@ -1109,8 +1109,17 @@ void Controller::saveUsername() {
 	if (!_savingData.username || *_savingData.username == username) {
 		return continueSave();
 	} else if (!channel) {
-		// #TODO groups autoconv
-		return continueSave();
+		const auto saveForChannel = [=](not_null<ChannelData*> channel) {
+			if (_peer->asChannel() == channel) {
+				saveUsername();
+			} else {
+				cancelSave();
+			}
+		};
+		_peer->session().api().migrateChat(
+			_peer->asChat(),
+			crl::guard(this, saveForChannel));
+		return;
 	}
 
 	request(MTPchannels_UpdateUsername(
@@ -1122,7 +1131,7 @@ void Controller::saveUsername() {
 			*_savingData.username);
 		continueSave();
 	}).fail([=](const RPCError &error) {
-		const auto type = error.type();
+		const auto &type = error.type();
 		if (type == qstr("USERNAME_NOT_MODIFIED")) {
 			channel->setName(
 				TextUtilities::SingleLine(channel->name),
@@ -1156,7 +1165,7 @@ void Controller::saveTitle() {
 		continueSave();
 	};
 	const auto onFail = [=](const RPCError &error) {
-		const auto type = error.type();
+		const auto &type = error.type();
 		if (type == qstr("CHAT_NOT_MODIFIED")
 			|| type == qstr("CHAT_TITLE_NOT_MODIFIED")) {
 			if (const auto channel = _peer->asChannel()) {
@@ -1209,7 +1218,7 @@ void Controller::saveDescription() {
 	)).done([=](const MTPBool &result) {
 		successCallback();
 	}).fail([=](const RPCError &error) {
-		auto type = error.type();
+		const auto &type = error.type();
 		if (type == qstr("CHAT_ABOUT_NOT_MODIFIED")) {
 			successCallback();
 			return;
@@ -1226,8 +1235,17 @@ void Controller::saveHistoryVisibility() {
 		|| *_savingData.hiddenPreHistory == hidden) {
 		return continueSave();
 	} else if (!channel) {
-		// #TODO groups autoconv
-		return continueSave();
+		const auto saveForChannel = [=](not_null<ChannelData*> channel) {
+			if (_peer->asChannel() == channel) {
+				saveHistoryVisibility();
+			} else {
+				cancelSave();
+			}
+		};
+		_peer->session().api().migrateChat(
+			_peer->asChat(),
+			crl::guard(this, saveForChannel));
+		return;
 	}
 	request(MTPchannels_TogglePreHistoryHidden(
 		channel->inputChannel,
diff --git a/Telegram/SourceFiles/data/data_peer.cpp b/Telegram/SourceFiles/data/data_peer.cpp
index 6358a484f..55e77b4df 100644
--- a/Telegram/SourceFiles/data/data_peer.cpp
+++ b/Telegram/SourceFiles/data/data_peer.cpp
@@ -489,6 +489,34 @@ const ChannelData *PeerData::asMegagroup() const {
 		: nullptr;
 }
 
+ChatData *PeerData::asChatNotMigrated() {
+	if (const auto chat = asChat()) {
+		return chat->migrateTo() ? nullptr : chat;
+	}
+	return nullptr;
+}
+
+const ChatData *PeerData::asChatNotMigrated() const {
+	if (const auto chat = asChat()) {
+		return chat->migrateTo() ? nullptr : chat;
+	}
+	return nullptr;
+}
+
+ChannelData *PeerData::asChannelOrMigrated() {
+	if (const auto channel = asChannel()) {
+		return channel;
+	}
+	return migrateTo();
+}
+
+const ChannelData *PeerData::asChannelOrMigrated() const {
+	if (const auto channel = asChannel()) {
+		return channel;
+	}
+	return migrateTo();
+}
+
 ChatData *PeerData::migrateFrom() const {
 	if (const auto megagroup = asMegagroup()) {
 		return megagroup->amIn()
diff --git a/Telegram/SourceFiles/data/data_peer.h b/Telegram/SourceFiles/data/data_peer.h
index f45a10d8c..02dee74c2 100644
--- a/Telegram/SourceFiles/data/data_peer.h
+++ b/Telegram/SourceFiles/data/data_peer.h
@@ -110,6 +110,10 @@ public:
 	[[nodiscard]] const ChannelData *asChannel() const;
 	[[nodiscard]] ChannelData *asMegagroup();
 	[[nodiscard]] const ChannelData *asMegagroup() const;
+	[[nodiscard]] ChatData *asChatNotMigrated();
+	[[nodiscard]] const ChatData *asChatNotMigrated() const;
+	[[nodiscard]] ChannelData *asChannelOrMigrated();
+	[[nodiscard]] const ChannelData *asChannelOrMigrated() const;
 
 	[[nodiscard]] ChatData *migrateFrom() const;
 	[[nodiscard]] ChannelData *migrateTo() const;
diff --git a/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp b/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp
index 286279476..61dc85a45 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.cpp
@@ -28,25 +28,20 @@ void ShowSearchFromBox(
 		peer,
 		callback = std::move(callback)
 	]() -> std::unique_ptr<PeerListController> {
-		if (peer) {
-			if (auto chat = peer->asChat()) {
-				return std::make_unique<Dialogs::ChatSearchFromController>(
-					navigation,
-					chat,
-					std::move(callback));
-			} else if (auto group = peer->asMegagroup()) {
-				return std::make_unique<Dialogs::ChannelSearchFromController>(
-					navigation,
-					group,
-					std::move(callback));
-			}
+		if (peer && (peer->isChat() || peer->isMegagroup())) {
+			return std::make_unique<Dialogs::SearchFromController>(
+				navigation,
+				peer,
+				std::move(callback));
 		}
 		return nullptr;
 	};
 	if (auto controller = createController()) {
 		auto subscription = std::make_shared<rpl::lifetime>();
 		auto box = Ui::show(Box<PeerListBox>(std::move(controller), [subscription](not_null<PeerListBox*> box) {
-			box->addButton(langFactory(lng_cancel), [box, subscription] { box->closeBox(); });
+			box->addButton(langFactory(lng_cancel), [box, subscription] {
+				box->closeBox();
+			});
 		}), LayerOption::KeepOther);
 		box->boxClosing() | rpl::start_with_next(
 			std::move(closedCallback),
@@ -54,106 +49,32 @@ void ShowSearchFromBox(
 	}
 }
 
-ChatSearchFromController::ChatSearchFromController(
+SearchFromController::SearchFromController(
 	not_null<Window::Navigation*> navigation,
-	not_null<ChatData*> chat,
-	Fn<void(not_null<UserData*>)> callback)
-: PeerListController()
-, _chat(chat)
-, _callback(std::move(callback)) {
-}
-
-void ChatSearchFromController::prepare() {
-	setSearchNoResultsText(lang(lng_blocked_list_not_found));
-	delegate()->peerListSetSearchMode(PeerListSearchMode::Enabled);
-	delegate()->peerListSetTitle(langFactory(lng_search_messages_from));
-
-	rebuildRows();
-
-	subscribe(Notify::PeerUpdated(), Notify::PeerUpdatedHandler(Notify::PeerUpdate::Flag::MembersChanged, [this](const Notify::PeerUpdate &update) {
-		if (update.peer == _chat) {
-			rebuildRows();
-		}
-	}));
-}
-
-void ChatSearchFromController::rowClicked(not_null<PeerListRow*> row) {
-	Expects(row->peer()->isUser());
-
-	const auto onstack = _callback;
-	onstack(row->peer()->asUser());
-}
-
-void ChatSearchFromController::rebuildRows() {
-	auto ms = getms();
-	auto wasEmpty = !delegate()->peerListFullRowsCount();
-
-	auto now = unixtime();
-	const auto byOnline = [&](not_null<UserData*> user) {
-		return Data::SortByOnlineValue(user, now);
-	};
-	auto ordered = QMultiMap<TimeId, not_null<UserData*>>();
-	if (_chat->noParticipantInfo()) {
-		Auth().api().requestFullPeer(_chat);
-	} else if (!_chat->participants.empty()) {
-		for (const auto user : _chat->participants) {
-			ordered.insertMulti(byOnline(user), user);
-		}
-	}
-	for_const (auto user, _chat->lastAuthors) {
-		if (user->isInaccessible()) continue;
-		appendRow(user);
-		if (!ordered.isEmpty()) {
-			ordered.remove(byOnline(user), user);
-		}
-	}
-	if (!ordered.isEmpty()) {
-		for (auto i = ordered.cend(), b = ordered.cbegin(); i != b;) {
-			appendRow(*(--i));
-		}
-	}
-	checkForEmptyRows();
-	delegate()->peerListRefreshRows();
-}
-
-void ChatSearchFromController::checkForEmptyRows() {
-	if (delegate()->peerListFullRowsCount()) {
-		setDescriptionText(QString());
-	} else {
-		setDescriptionText(lang(lng_contacts_loading));
-	}
-}
-
-void ChatSearchFromController::appendRow(not_null<UserData*> user) {
-	if (!delegate()->peerListFindRow(user->id)) {
-		delegate()->peerListAppendRow(std::make_unique<PeerListRow>(user));
-	}
-}
-
-ChannelSearchFromController::ChannelSearchFromController(
-	not_null<Window::Navigation*> navigation,
-	not_null<ChannelData*> channel,
+	not_null<PeerData*> peer,
 	Fn<void(not_null<UserData*>)> callback)
 : ParticipantsBoxController(
 	navigation,
-	channel,
+	peer,
 	ParticipantsBoxController::Role::Members)
 , _callback(std::move(callback)) {
 }
 
-void ChannelSearchFromController::prepare() {
+void SearchFromController::prepare() {
 	ParticipantsBoxController::prepare();
 	delegate()->peerListSetTitle(langFactory(lng_search_messages_from));
 }
 
-void ChannelSearchFromController::rowClicked(not_null<PeerListRow*> row) {
+void SearchFromController::rowClicked(not_null<PeerListRow*> row) {
 	Expects(row->peer()->isUser());
 
-	const auto onstack = _callback;
-	onstack(row->peer()->asUser());
+	if (const auto onstack = base::duplicate(_callback)) {
+		onstack(row->peer()->asUser());
+	}
 }
 
-std::unique_ptr<PeerListRow> ChannelSearchFromController::createRow(not_null<UserData*> user) const {
+std::unique_ptr<PeerListRow> SearchFromController::createRow(
+		not_null<UserData*> user) const {
 	return std::make_unique<PeerListRow>(user);
 }
 
diff --git a/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.h b/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.h
index 9a7a12c9d..8153c5f20 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.h
+++ b/Telegram/SourceFiles/dialogs/dialogs_search_from_controllers.h
@@ -18,31 +18,11 @@ void ShowSearchFromBox(
 	Fn<void(not_null<UserData*>)> callback,
 	Fn<void()> closedCallback);
 
-class ChatSearchFromController : public PeerListController, protected base::Subscriber {
+class SearchFromController : public ParticipantsBoxController {
 public:
-	ChatSearchFromController(
+	SearchFromController(
 		not_null<Window::Navigation*> navigation,
-		not_null<ChatData*> chat,
-		Fn<void(not_null<UserData*>)> callback);
-
-	void prepare() override;
-	void rowClicked(not_null<PeerListRow*> row) override;
-
-private:
-	void rebuildRows();
-	void checkForEmptyRows();
-	void appendRow(not_null<UserData*> user);
-
-	not_null<ChatData*> _chat;
-	Fn<void(not_null<UserData*>)> _callback;
-
-};
-
-class ChannelSearchFromController : public ParticipantsBoxController {
-public:
-	ChannelSearchFromController(
-		not_null<Window::Navigation*> navigation,
-		not_null<ChannelData*> channel,
+		not_null<PeerData*> peer,
 		Fn<void(not_null<UserData*>)> callback);
 
 	void prepare() override;
diff --git a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
index a1f8b67ef..b4365a85b 100644
--- a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
+++ b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
@@ -9,7 +9,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "mtproto/mtp_instance.h"
 #include "mtproto/rpc_sender.h"
-#include "mtproto/session.h"
 
 namespace MTP {
 
@@ -180,11 +179,13 @@ void ConcurrentSender::senderRequestDone(
 		bytes::const_span result) {
 	if (auto handlers = _requests.take(requestId)) {
 		try {
-			std::move(handlers->done)(requestId, result);
+			handlers->done(requestId, result);
 		} catch (Exception &e) {
-			std::move(handlers->fail)(requestId, internal::rpcClientError(
-				"RESPONSE_PARSE_FAILED",
-				QString("exception text: ") + e.what()));
+			handlers->fail(
+				requestId,
+				RPCError::Local(
+					"RESPONSE_PARSE_FAILED",
+					QString("exception text: ") + e.what()));
 		}
 	}
 }
@@ -193,7 +194,7 @@ void ConcurrentSender::senderRequestFail(
 		mtpRequestId requestId,
 		RPCError &&error) {
 	if (auto handlers = _requests.take(requestId)) {
-		std::move(handlers->fail)(requestId, std::move(error));
+		handlers->fail(requestId, std::move(error));
 	}
 }
 
diff --git a/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp b/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp
index 752698250..e9746708d 100644
--- a/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp
+++ b/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp
@@ -7,7 +7,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/dedicated_file_loader.h"
 
-#include "mtproto/session.h"
 #include "auth_session.h"
 #include "messenger.h"
 
@@ -110,7 +109,9 @@ void WeakInstance::die() {
 		if (instance) {
 			instance->cancel(requestId);
 		}
-		fail(MTP::internal::rpcClientError("UNAVAILABLE"));
+		fail(RPCError::Local(
+			"UNAVAILABLE",
+			"MTP instance is not available."));
 	}
 }
 
@@ -125,7 +126,9 @@ bool WeakInstance::removeRequest(mtpRequestId requestId) {
 void WeakInstance::reportUnavailable(
 		Fn<void(const RPCError &error)> callback) {
 	InvokeQueued(this, [=] {
-		callback(MTP::internal::rpcClientError("UNAVAILABLE"));
+		callback(RPCError::Local(
+			"UNAVAILABLE",
+			"MTP instance is not available."));
 	});
 }
 
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 675fe4ac2..590fe3cb2 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -956,7 +956,14 @@ void Instance::Private::clearCallbacks(mtpRequestId requestId, int32 errorCode)
 			"Request: %1, error code: %2"
 			).arg(requestId
 			).arg(errorCode));
-		rpcErrorOccured(requestId, h, internal::rpcClientError("CLEAR_CALLBACK", QString("did not handle request %1, error code %2").arg(requestId).arg(errorCode)));
+		rpcErrorOccured(
+			requestId,
+			h,
+			RPCError::Local(
+				"CLEAR_CALLBACK",
+				QString("did not handle request %1, error code %2"
+				).arg(requestId
+				).arg(errorCode)));
 	}
 }
 
@@ -1017,14 +1024,13 @@ void Instance::Private::execCallback(
 		}
 	}
 	if (h.onDone || h.onFail) {
-		const auto handleError = [&](const MTPRpcError &error) {
-			const auto wrapped = RPCError(error);
+		const auto handleError = [&](const RPCError &error) {
 			DEBUG_LOG(("RPC Info: "
 				"error received, code %1, type %2, description: %3"
-				).arg(wrapped.code()
-				).arg(wrapped.type()
-				).arg(wrapped.description()));
-			if (rpcErrorOccured(requestId, h, wrapped)) {
+				).arg(error.code()
+				).arg(error.type()
+				).arg(error.description()));
+			if (rpcErrorOccured(requestId, h, error)) {
 				unregisterRequest(requestId);
 			} else {
 				QMutexLocker locker(&_parserMapLock);
@@ -1045,7 +1051,7 @@ void Instance::Private::execCallback(
 				unregisterRequest(requestId);
 			}
 		} catch (Exception &e) {
-			handleError(internal::rpcClientError(
+			handleError(RPCError::Local(
 				"RESPONSE_PARSE_FAILED",
 				QString("exception text: ") + e.what()));
 		}
@@ -1103,7 +1109,10 @@ void Instance::Private::importDone(const MTPauth_Authorization &result, mtpReque
 		//
 		// Don't log out on export/import problems, perhaps this is a server side error.
 		//
-		//RPCError error(internal::rpcClientError("AUTH_IMPORT_FAIL", QString("did not find import request in requestsByDC, request %1").arg(requestId)));
+		//const auto error = RPCError::Local(
+		//	"AUTH_IMPORT_FAIL",
+		//	QString("did not find import request in requestsByDC, "
+		//		"request %1").arg(requestId));
 		//if (_globalHandler.onFail && hasAuthorization()) {
 		//	(*_globalHandler.onFail)(requestId, error); // auth failed in main dc
 		//}
@@ -1156,7 +1165,10 @@ void Instance::Private::exportDone(const MTPauth_ExportedAuthorization &result,
 		//
 		// Don't log out on export/import problems, perhaps this is a server side error.
 		//
-		//RPCError error(internal::rpcClientError("AUTH_IMPORT_FAIL", QString("did not find target dcWithShift, request %1").arg(requestId)));
+		//const auto error = RPCError::Local(
+		//	"AUTH_IMPORT_FAIL",
+		//	QString("did not find target dcWithShift, request %1"
+		//	).arg(requestId));
 		//if (_globalHandler.onFail && hasAuthorization()) {
 		//	(*_globalHandler.onFail)(requestId, error); // auth failed in main dc
 		//}
diff --git a/Telegram/SourceFiles/mtproto/rpc_sender.h b/Telegram/SourceFiles/mtproto/rpc_sender.h
index f92a9a019..84c47449e 100644
--- a/Telegram/SourceFiles/mtproto/rpc_sender.h
+++ b/Telegram/SourceFiles/mtproto/rpc_sender.h
@@ -32,10 +32,21 @@ public:
 		TimeoutError
 	};
 
-private:
+	static RPCError Local(const QString &type, const QString &description) {
+		return MTP_rpc_error(
+			MTP_int(0),
+			MTP_bytes(
+			("CLIENT_"
+				+ type
+				+ (description.length()
+					? (": " + description)
+					: QString())).toUtf8()));
+	}
 
+private:
 	int32 _code;
 	QString _type, _description;
+
 };
 
 namespace MTP {
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index be7573c10..6f5ef367f 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -156,8 +156,11 @@ void Session::createDcData() {
 	connect(dc.get(), SIGNAL(connectionWasInited()), this, SLOT(connectionWasInitedForDC()), Qt::QueuedConnection);
 }
 
-bool Session::rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err) { // return true if need to clean request data
-	return _instance->rpcErrorOccured(requestId, onFail, err);
+bool Session::rpcErrorOccured(
+		mtpRequestId requestId,
+		const RPCFailHandlerPtr &onFail,
+		const RPCError &error) { // return true if need to clean request data
+	return _instance->rpcErrorOccured(requestId, onFail, error);
 }
 
 void Session::restart() {
@@ -618,9 +621,5 @@ Session::~Session() {
 	Assert(_connection == nullptr);
 }
 
-MTPrpcError rpcClientError(const QString &type, const QString &description) {
-	return MTP_rpc_error(MTP_int(0), MTP_string(("CLIENT_" + type + (description.length() ? (": " + description) : "")).toUtf8().constData()));
-}
-
 } // namespace internal
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index da27be0d8..ebecb0389 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -402,7 +402,5 @@ inline not_null<QReadWriteLock*> SessionData::keyMutex() const {
 	return _owner->keyMutex();
 }
 
-MTPrpcError rpcClientError(const QString &type, const QString &description = QString());
-
 } // namespace internal
 } // namespace MTP
diff --git a/Telegram/SourceFiles/window/window_peer_menu.cpp b/Telegram/SourceFiles/window/window_peer_menu.cpp
index 837b9760c..1e7d853c3 100644
--- a/Telegram/SourceFiles/window/window_peer_menu.cpp
+++ b/Telegram/SourceFiles/window/window_peer_menu.cpp
@@ -107,11 +107,7 @@ History *FindWastedPin() {
 }
 
 void AddChatMembers(not_null<ChatData*> chat) {
-	if (chat->count >= Global::ChatSizeMax() && chat->amCreator()) {
-		// #TODO convert and add inside AddParticipantsBoxController?
-	} else {
-		AddParticipantsBoxController::Start(chat);
-	}
+	AddParticipantsBoxController::Start(chat);
 }
 
 bool PinnedLimitReached(Dialogs::Key key) {