diff --git a/build.html b/build.html
index dd5030c..409fb28 100644
--- a/build.html
+++ b/build.html
@@ -678,7 +678,7 @@ function onOptionsChanged() {
   document.getElementById('buildCommands').innerHTML = '<ul><li>' + commands.join('</li><li>') + '</li></ul>';
   document.getElementById('copyBuildCommandsButton').style.display = commands.includes('exit') ? 'none' : 'block';
 }
-  
+
 function copyBuildInstructions() {
   var text = document.getElementById('buildCommands').innerText;
 
diff --git a/telegram-bot-api/Client.cpp b/telegram-bot-api/Client.cpp
index 9f945b4..aec0787 100644
--- a/telegram-bot-api/Client.cpp
+++ b/telegram-bot-api/Client.cpp
@@ -8,11 +8,11 @@
 
 #include "telegram-bot-api/ClientParameters.h"
 
+#include "td/db/TQueue.h"
+
 #include "td/actor/PromiseFuture.h"
 #include "td/actor/SleepActor.h"
 
-#include "td/db/TQueue.h"
-
 #include "td/utils/algorithm.h"
 #include "td/utils/base64.h"
 #include "td/utils/filesystem.h"
@@ -23,7 +23,6 @@
 #include "td/utils/PathView.h"
 #include "td/utils/port/path.h"
 #include "td/utils/port/Stat.h"
-#include "td/utils/Random.h"
 #include "td/utils/Slice.h"
 #include "td/utils/SliceBuilder.h"
 #include "td/utils/Span.h"
@@ -276,7 +275,7 @@ bool Client::init_methods() {
   return true;
 }
 
-class Client::JsonFile : public Jsonable {
+class Client::JsonFile final : public Jsonable {
  public:
   JsonFile(const td_api::file *file, const Client *client) : file_(file), client_(client) {
   }
@@ -290,7 +289,7 @@ class Client::JsonFile : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonDatedFile : public Jsonable {
+class Client::JsonDatedFile final : public Jsonable {
  public:
   JsonDatedFile(const td_api::datedFile *file, const Client *client) : file_(file), client_(client) {
   }
@@ -305,7 +304,7 @@ class Client::JsonDatedFile : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonDatedFiles : public Jsonable {
+class Client::JsonDatedFiles final : public Jsonable {
  public:
   JsonDatedFiles(const td::vector<object_ptr<td_api::datedFile>> &files, const Client *client)
       : files_(files), client_(client) {
@@ -322,7 +321,7 @@ class Client::JsonDatedFiles : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonUser : public Jsonable {
+class Client::JsonUser final : public Jsonable {
  public:
   JsonUser(int64 user_id, const Client *client, bool full_bot_info = false)
       : user_id_(user_id), client_(client), full_bot_info_(full_bot_info) {
@@ -356,7 +355,7 @@ class Client::JsonUser : public Jsonable {
   bool full_bot_info_;
 };
 
-class Client::JsonUsers : public Jsonable {
+class Client::JsonUsers final : public Jsonable {
  public:
   JsonUsers(const td::vector<int64> &user_ids, const Client *client) : user_ids_(user_ids), client_(client) {
   }
@@ -372,7 +371,7 @@ class Client::JsonUsers : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonEntity : public Jsonable {
+class Client::JsonEntity final : public Jsonable {
  public:
   JsonEntity(const td_api::textEntity *entity, const Client *client) : entity_(entity), client_(client) {
   }
@@ -454,7 +453,7 @@ class Client::JsonEntity : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonVectorEntities : public Jsonable {
+class Client::JsonVectorEntities final : public Jsonable {
  public:
   JsonVectorEntities(const td::vector<object_ptr<td_api::textEntity>> &entities, const Client *client)
       : entities_(entities), client_(client) {
@@ -475,7 +474,7 @@ class Client::JsonVectorEntities : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonLocation : public Jsonable {
+class Client::JsonLocation final : public Jsonable {
  public:
   explicit JsonLocation(const td_api::location *location, double expires_in = 0.0, int32 live_period = 0,
                         int32 heading = 0, int32 proximity_alert_radius = 0)
@@ -511,7 +510,7 @@ class Client::JsonLocation : public Jsonable {
   int32 proximity_alert_radius_;
 };
 
-class Client::JsonChatPermissions : public Jsonable {
+class Client::JsonChatPermissions final : public Jsonable {
  public:
   explicit JsonChatPermissions(const td_api::chatPermissions *chat_permissions) : chat_permissions_(chat_permissions) {
   }
@@ -524,7 +523,7 @@ class Client::JsonChatPermissions : public Jsonable {
   const td_api::chatPermissions *chat_permissions_;
 };
 
-class Client::JsonChatPhotoInfo : public Jsonable {
+class Client::JsonChatPhotoInfo final : public Jsonable {
  public:
   explicit JsonChatPhotoInfo(const td_api::chatPhotoInfo *chat_photo) : chat_photo_(chat_photo) {
   }
@@ -540,7 +539,7 @@ class Client::JsonChatPhotoInfo : public Jsonable {
   const td_api::chatPhotoInfo *chat_photo_;
 };
 
-class Client::JsonChatLocation : public Jsonable {
+class Client::JsonChatLocation final : public Jsonable {
  public:
   explicit JsonChatLocation(const td_api::chatLocation *chat_location) : chat_location_(chat_location) {
   }
@@ -554,7 +553,7 @@ class Client::JsonChatLocation : public Jsonable {
   const td_api::chatLocation *chat_location_;
 };
 
-class Client::JsonChatInviteLink : public Jsonable {
+class Client::JsonChatInviteLink final : public Jsonable {
  public:
   JsonChatInviteLink(const td_api::chatInviteLink *chat_invite_link, const Client *client)
       : chat_invite_link_(chat_invite_link), client_(client) {
@@ -585,7 +584,7 @@ class Client::JsonChatInviteLink : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonMessage : public Jsonable {
+class Client::JsonMessage final : public Jsonable {
  public:
   JsonMessage(const MessageInfo *message, bool need_reply, const td::string &source, const Client *client)
       : message_(message), need_reply_(need_reply), source_(source), client_(client) {
@@ -610,7 +609,7 @@ class Client::JsonMessage : public Jsonable {
   }
 };
 
-class Client::JsonChat : public Jsonable {
+class Client::JsonChat final : public Jsonable {
  public:
   JsonChat(int64 chat_id, bool is_full, const Client *client, int64 pinned_message_id = -1)
       : chat_id_(chat_id), is_full_(is_full), client_(client), pinned_message_id_(pinned_message_id) {
@@ -746,7 +745,7 @@ class Client::JsonChat : public Jsonable {
   int64 pinned_message_id_;
 };
 
-class Client::JsonMessageSender : public Jsonable {
+class Client::JsonMessageSender final : public Jsonable {
  public:
   JsonMessageSender(const td_api::MessageSender *sender_id, const Client *client)
       : sender_id_(sender_id), client_(client) {
@@ -774,7 +773,7 @@ class Client::JsonMessageSender : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonMessages : public Jsonable {
+class Client::JsonMessages final : public Jsonable {
  public:
   explicit JsonMessages(const td::vector<td::string> &messages) : messages_(messages) {
   }
@@ -789,7 +788,7 @@ class Client::JsonMessages : public Jsonable {
   const td::vector<td::string> &messages_;
 };
 
-class Client::JsonAnimation : public Jsonable {
+class Client::JsonAnimation final : public Jsonable {
  public:
   JsonAnimation(const td_api::animation *animation, bool as_document, const Client *client)
       : animation_(animation), as_document_(as_document), client_(client) {
@@ -817,7 +816,7 @@ class Client::JsonAnimation : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonAudio : public Jsonable {
+class Client::JsonAudio final : public Jsonable {
  public:
   JsonAudio(const td_api::audio *audio, const Client *client) : audio_(audio), client_(client) {
   }
@@ -845,7 +844,7 @@ class Client::JsonAudio : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonDocument : public Jsonable {
+class Client::JsonDocument final : public Jsonable {
  public:
   JsonDocument(const td_api::document *document, const Client *client) : document_(document), client_(client) {
   }
@@ -866,7 +865,7 @@ class Client::JsonDocument : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonPhotoSize : public Jsonable {
+class Client::JsonPhotoSize final : public Jsonable {
  public:
   JsonPhotoSize(const td_api::photoSize *photo_size, const Client *client) : photo_size_(photo_size), client_(client) {
   }
@@ -882,7 +881,7 @@ class Client::JsonPhotoSize : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonThumbnail : public Jsonable {
+class Client::JsonThumbnail final : public Jsonable {
  public:
   JsonThumbnail(const td_api::thumbnail *thumbnail, const Client *client) : thumbnail_(thumbnail), client_(client) {
   }
@@ -898,7 +897,7 @@ class Client::JsonThumbnail : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonPhoto : public Jsonable {
+class Client::JsonPhoto final : public Jsonable {
  public:
   JsonPhoto(const td_api::photo *photo, const Client *client) : photo_(photo), client_(client) {
   }
@@ -916,7 +915,7 @@ class Client::JsonPhoto : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonChatPhoto : public Jsonable {
+class Client::JsonChatPhoto final : public Jsonable {
  public:
   JsonChatPhoto(const td_api::chatPhoto *photo, const Client *client) : photo_(photo), client_(client) {
   }
@@ -934,7 +933,7 @@ class Client::JsonChatPhoto : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonMaskPosition : public Jsonable {
+class Client::JsonMaskPosition final : public Jsonable {
  public:
   explicit JsonMaskPosition(const td_api::maskPosition *mask_position) : mask_position_(mask_position) {
   }
@@ -950,7 +949,7 @@ class Client::JsonMaskPosition : public Jsonable {
   const td_api::maskPosition *mask_position_;
 };
 
-class Client::JsonSticker : public Jsonable {
+class Client::JsonSticker final : public Jsonable {
  public:
   JsonSticker(const td_api::sticker *sticker, const Client *client) : sticker_(sticker), client_(client) {
   }
@@ -978,7 +977,7 @@ class Client::JsonSticker : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonStickers : public Jsonable {
+class Client::JsonStickers final : public Jsonable {
  public:
   JsonStickers(const td::vector<object_ptr<td_api::sticker>> &stickers, const Client *client)
       : stickers_(stickers), client_(client) {
@@ -995,7 +994,7 @@ class Client::JsonStickers : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonVideo : public Jsonable {
+class Client::JsonVideo final : public Jsonable {
  public:
   JsonVideo(const td_api::video *video, const Client *client) : video_(video), client_(client) {
   }
@@ -1019,7 +1018,7 @@ class Client::JsonVideo : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonVideoNote : public Jsonable {
+class Client::JsonVideoNote final : public Jsonable {
  public:
   JsonVideoNote(const td_api::videoNote *video_note, const Client *client) : video_note_(video_note), client_(client) {
   }
@@ -1036,7 +1035,7 @@ class Client::JsonVideoNote : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonVoiceNote : public Jsonable {
+class Client::JsonVoiceNote final : public Jsonable {
  public:
   JsonVoiceNote(const td_api::voiceNote *voice_note, const Client *client) : voice_note_(voice_note), client_(client) {
   }
@@ -1054,7 +1053,7 @@ class Client::JsonVoiceNote : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonVenue : public Jsonable {
+class Client::JsonVenue final : public Jsonable {
  public:
   explicit JsonVenue(const td_api::venue *venue) : venue_(venue) {
   }
@@ -1085,7 +1084,7 @@ class Client::JsonVenue : public Jsonable {
   const td_api::venue *venue_;
 };
 
-class Client::JsonContact : public Jsonable {
+class Client::JsonContact final : public Jsonable {
  public:
   explicit JsonContact(const td_api::contact *contact) : contact_(contact) {
   }
@@ -1108,7 +1107,7 @@ class Client::JsonContact : public Jsonable {
   const td_api::contact *contact_;
 };
 
-class Client::JsonDice : public Jsonable {
+class Client::JsonDice final : public Jsonable {
  public:
   JsonDice(const td::string &emoji, int32 value) : emoji_(emoji), value_(value) {
   }
@@ -1123,7 +1122,7 @@ class Client::JsonDice : public Jsonable {
   int32 value_;
 };
 
-class Client::JsonGame : public Jsonable {
+class Client::JsonGame final : public Jsonable {
  public:
   JsonGame(const td_api::game *game, const Client *client) : game_(game), client_(client) {
   }
@@ -1149,7 +1148,7 @@ class Client::JsonGame : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonInvoice : public Jsonable {
+class Client::JsonInvoice final : public Jsonable {
  public:
   explicit JsonInvoice(const td_api::messageInvoice *invoice) : invoice_(invoice) {
   }
@@ -1170,7 +1169,7 @@ class Client::JsonInvoice : public Jsonable {
   const td_api::messageInvoice *invoice_;
 };
 
-class Client::JsonPollOption : public Jsonable {
+class Client::JsonPollOption final : public Jsonable {
  public:
   explicit JsonPollOption(const td_api::pollOption *option) : option_(option) {
   }
@@ -1185,7 +1184,7 @@ class Client::JsonPollOption : public Jsonable {
   const td_api::pollOption *option_;
 };
 
-class Client::JsonPoll : public Jsonable {
+class Client::JsonPoll final : public Jsonable {
  public:
   JsonPoll(const td_api::poll *poll, const Client *client) : poll_(poll), client_(client) {
   }
@@ -1232,7 +1231,7 @@ class Client::JsonPoll : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonPollAnswer : public Jsonable {
+class Client::JsonPollAnswer final : public Jsonable {
  public:
   JsonPollAnswer(const td_api::updatePollAnswer *poll_answer, const Client *client)
       : poll_answer_(poll_answer), client_(client) {
@@ -1249,7 +1248,7 @@ class Client::JsonPollAnswer : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonAddress : public Jsonable {
+class Client::JsonAddress final : public Jsonable {
  public:
   explicit JsonAddress(const td_api::address *address) : address_(address) {
   }
@@ -1267,7 +1266,7 @@ class Client::JsonAddress : public Jsonable {
   const td_api::address *address_;
 };
 
-class Client::JsonOrderInfo : public Jsonable {
+class Client::JsonOrderInfo final : public Jsonable {
  public:
   explicit JsonOrderInfo(const td_api::orderInfo *order_info) : order_info_(order_info) {
   }
@@ -1291,7 +1290,7 @@ class Client::JsonOrderInfo : public Jsonable {
   const td_api::orderInfo *order_info_;
 };
 
-class Client::JsonSuccessfulPaymentBot : public Jsonable {
+class Client::JsonSuccessfulPaymentBot final : public Jsonable {
  public:
   explicit JsonSuccessfulPaymentBot(const td_api::messagePaymentSuccessfulBot *successful_payment)
       : successful_payment_(successful_payment) {
@@ -1321,7 +1320,7 @@ class Client::JsonSuccessfulPaymentBot : public Jsonable {
   const td_api::messagePaymentSuccessfulBot *successful_payment_;
 };
 
-class Client::JsonEncryptedPassportElement : public Jsonable {
+class Client::JsonEncryptedPassportElement final : public Jsonable {
  public:
   JsonEncryptedPassportElement(const td_api::encryptedPassportElement *element, const Client *client)
       : element_(element), client_(client) {
@@ -1388,7 +1387,7 @@ class Client::JsonEncryptedPassportElement : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonEncryptedCredentials : public Jsonable {
+class Client::JsonEncryptedCredentials final : public Jsonable {
  public:
   explicit JsonEncryptedCredentials(const td_api::encryptedCredentials *credentials) : credentials_(credentials) {
   }
@@ -1403,7 +1402,7 @@ class Client::JsonEncryptedCredentials : public Jsonable {
   const td_api::encryptedCredentials *credentials_;
 };
 
-class Client::JsonPassportData : public Jsonable {
+class Client::JsonPassportData final : public Jsonable {
  public:
   JsonPassportData(const td_api::messagePassportDataReceived *passport_data, const Client *client)
       : passport_data_(passport_data), client_(client) {
@@ -1421,7 +1420,7 @@ class Client::JsonPassportData : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonProximityAlertTriggered : public Jsonable {
+class Client::JsonProximityAlertTriggered final : public Jsonable {
  public:
   JsonProximityAlertTriggered(const td_api::messageProximityAlertTriggered *proximity_alert_triggered,
                               const Client *client)
@@ -1439,7 +1438,7 @@ class Client::JsonProximityAlertTriggered : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonVideoChatScheduled : public Jsonable {
+class Client::JsonVideoChatScheduled final : public Jsonable {
  public:
   explicit JsonVideoChatScheduled(const td_api::messageVideoChatScheduled *video_chat_scheduled)
       : video_chat_scheduled_(video_chat_scheduled) {
@@ -1453,14 +1452,14 @@ class Client::JsonVideoChatScheduled : public Jsonable {
   const td_api::messageVideoChatScheduled *video_chat_scheduled_;
 };
 
-class Client::JsonVideoChatStarted : public Jsonable {
+class Client::JsonVideoChatStarted final : public Jsonable {
  public:
   void store(JsonValueScope *scope) const {
     auto object = scope->enter_object();
   }
 };
 
-class Client::JsonVideoChatEnded : public Jsonable {
+class Client::JsonVideoChatEnded final : public Jsonable {
  public:
   explicit JsonVideoChatEnded(const td_api::messageVideoChatEnded *video_chat_ended)
       : video_chat_ended_(video_chat_ended) {
@@ -1474,7 +1473,7 @@ class Client::JsonVideoChatEnded : public Jsonable {
   const td_api::messageVideoChatEnded *video_chat_ended_;
 };
 
-class Client::JsonInviteVideoChatParticipants : public Jsonable {
+class Client::JsonInviteVideoChatParticipants final : public Jsonable {
  public:
   JsonInviteVideoChatParticipants(const td_api::messageInviteVideoChatParticipants *invite_video_chat_participants,
                                   const Client *client)
@@ -1490,7 +1489,7 @@ class Client::JsonInviteVideoChatParticipants : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonChatSetTtl : public Jsonable {
+class Client::JsonChatSetTtl final : public Jsonable {
  public:
   explicit JsonChatSetTtl(const td_api::messageChatSetTtl *chat_set_ttl) : chat_set_ttl_(chat_set_ttl) {
   }
@@ -1503,14 +1502,14 @@ class Client::JsonChatSetTtl : public Jsonable {
   const td_api::messageChatSetTtl *chat_set_ttl_;
 };
 
-class Client::JsonCallbackGame : public Jsonable {
+class Client::JsonCallbackGame final : public Jsonable {
  public:
   void store(JsonValueScope *scope) const {
     auto object = scope->enter_object();
   }
 };
 
-class Client::JsonInlineKeyboardButton : public Jsonable {
+class Client::JsonInlineKeyboardButton final : public Jsonable {
  public:
   explicit JsonInlineKeyboardButton(const td_api::inlineKeyboardButton *button) : button_(button) {
   }
@@ -1568,7 +1567,7 @@ class Client::JsonInlineKeyboardButton : public Jsonable {
   const td_api::inlineKeyboardButton *button_;
 };
 
-class Client::JsonInlineKeyboard : public Jsonable {
+class Client::JsonInlineKeyboard final : public Jsonable {
  public:
   explicit JsonInlineKeyboard(const td_api::replyMarkupInlineKeyboard *inline_keyboard)
       : inline_keyboard_(inline_keyboard) {
@@ -1584,7 +1583,7 @@ class Client::JsonInlineKeyboard : public Jsonable {
   const td_api::replyMarkupInlineKeyboard *inline_keyboard_;
 };
 
-class Client::JsonReplyMarkup : public Jsonable {
+class Client::JsonReplyMarkup final : public Jsonable {
  public:
   explicit JsonReplyMarkup(const td_api::ReplyMarkup *reply_markup) : reply_markup_(reply_markup) {
   }
@@ -1936,7 +1935,7 @@ void Client::JsonMessage::store(JsonValueScope *scope) const {
   }
 }
 
-class Client::JsonDeletedMessage : public Jsonable {
+class Client::JsonDeletedMessage final : public Jsonable {
  public:
   JsonDeletedMessage(int64 chat_id, int64 message_id, const Client *client)
       : chat_id_(chat_id), message_id_(message_id), client_(client) {
@@ -1954,7 +1953,7 @@ class Client::JsonDeletedMessage : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonMessageId : public Jsonable {
+class Client::JsonMessageId final : public Jsonable {
  public:
   explicit JsonMessageId(int64 message_id) : message_id_(message_id) {
   }
@@ -1967,7 +1966,7 @@ class Client::JsonMessageId : public Jsonable {
   int64 message_id_;
 };
 
-class Client::JsonInlineQuery : public Jsonable {
+class Client::JsonInlineQuery final : public Jsonable {
  public:
   JsonInlineQuery(int64 inline_query_id, int64 sender_user_id, const td_api::location *user_location,
                   const td_api::ChatType *chat_type, const td::string &query, const td::string &offset,
@@ -2033,7 +2032,7 @@ class Client::JsonInlineQuery : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonChosenInlineResult : public Jsonable {
+class Client::JsonChosenInlineResult final : public Jsonable {
  public:
   JsonChosenInlineResult(int64 sender_user_id, const td_api::location *user_location, const td::string &query,
                          const td::string &result_id, const td::string &inline_message_id, const Client *client)
@@ -2067,7 +2066,7 @@ class Client::JsonChosenInlineResult : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonCallbackQuery : public Jsonable {
+class Client::JsonCallbackQuery final : public Jsonable {
  public:
   JsonCallbackQuery(int64 callback_query_id, int64 sender_user_id, int64 chat_id, int64 message_id,
                     const MessageInfo *message_info, int64 chat_instance, td_api::CallbackQueryPayload *payload,
@@ -2106,7 +2105,7 @@ class Client::JsonCallbackQuery : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonInlineCallbackQuery : public Jsonable {
+class Client::JsonInlineCallbackQuery final : public Jsonable {
  public:
   JsonInlineCallbackQuery(int64 callback_query_id, int64 sender_user_id, const td::string &inline_message_id,
                           int64 chat_instance, td_api::CallbackQueryPayload *payload, const Client *client)
@@ -2136,7 +2135,7 @@ class Client::JsonInlineCallbackQuery : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonShippingQuery : public Jsonable {
+class Client::JsonShippingQuery final : public Jsonable {
  public:
   JsonShippingQuery(const td_api::updateNewShippingQuery *query, const Client *client)
       : query_(query), client_(client) {
@@ -2160,7 +2159,7 @@ class Client::JsonShippingQuery : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonPreCheckoutQuery : public Jsonable {
+class Client::JsonPreCheckoutQuery final : public Jsonable {
  public:
   JsonPreCheckoutQuery(const td_api::updateNewPreCheckoutQuery *query, const Client *client)
       : query_(query), client_(client) {
@@ -2191,7 +2190,7 @@ class Client::JsonPreCheckoutQuery : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonCustomJson : public Jsonable {
+class Client::JsonCustomJson final : public Jsonable {
  public:
   explicit JsonCustomJson(const td::string &json) : json_(json) {
   }
@@ -2204,7 +2203,7 @@ class Client::JsonCustomJson : public Jsonable {
   const td::string &json_;
 };
 
-class Client::JsonBotCommand : public Jsonable {
+class Client::JsonBotCommand final : public Jsonable {
  public:
   explicit JsonBotCommand(const td_api::botCommand *command) : command_(command) {
   }
@@ -2218,7 +2217,7 @@ class Client::JsonBotCommand : public Jsonable {
   const td_api::botCommand *command_;
 };
 
-class Client::JsonChatPhotos : public Jsonable {
+class Client::JsonChatPhotos final : public Jsonable {
  public:
   JsonChatPhotos(const td_api::chatPhotos *photos, const Client *client) : photos_(photos), client_(client) {
   }
@@ -2234,7 +2233,7 @@ class Client::JsonChatPhotos : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonChatMember : public Jsonable {
+class Client::JsonChatMember final : public Jsonable {
  public:
   JsonChatMember(const td_api::chatMember *member, Client::ChatType chat_type, const Client *client)
       : member_(member), chat_type_(chat_type), client_(client) {
@@ -2316,7 +2315,7 @@ class Client::JsonChatMember : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonChatMembers : public Jsonable {
+class Client::JsonChatMembers final : public Jsonable {
  public:
   JsonChatMembers(const td::vector<object_ptr<td_api::chatMember>> &members, Client::ChatType chat_type,
                   bool administrators_only, const Client *client)
@@ -2353,7 +2352,7 @@ class Client::JsonChatMembers : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonChatMemberUpdated : public Jsonable {
+class Client::JsonChatMemberUpdated final : public Jsonable {
  public:
   JsonChatMemberUpdated(const td_api::updateChatMember *update, const Client *client)
       : update_(update), client_(client) {
@@ -2376,7 +2375,7 @@ class Client::JsonChatMemberUpdated : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonChatJoinRequest : public Jsonable {
+class Client::JsonChatJoinRequest final : public Jsonable {
  public:
   JsonChatJoinRequest(const td_api::updateNewChatJoinRequest *update, const Client *client)
       : update_(update), client_(client) {
@@ -2399,7 +2398,7 @@ class Client::JsonChatJoinRequest : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonGameHighScore : public Jsonable {
+class Client::JsonGameHighScore final : public Jsonable {
  public:
   JsonGameHighScore(const td_api::gameHighScore *score, const Client *client) : score_(score), client_(client) {
   }
@@ -2416,7 +2415,7 @@ class Client::JsonGameHighScore : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonUpdateTypes : public Jsonable {
+class Client::JsonUpdateTypes final : public Jsonable {
  public:
   explicit JsonUpdateTypes(td::uint32 update_types) : update_types_(update_types) {
   }
@@ -2436,7 +2435,7 @@ class Client::JsonUpdateTypes : public Jsonable {
   td::uint32 update_types_;
 };
 
-class Client::JsonWebhookInfo : public Jsonable {
+class Client::JsonWebhookInfo final : public Jsonable {
  public:
   explicit JsonWebhookInfo(const Client *client) : client_(client) {
   }
@@ -2474,7 +2473,7 @@ class Client::JsonWebhookInfo : public Jsonable {
   const Client *client_;
 };
 
-class Client::JsonStickerSet : public Jsonable {
+class Client::JsonStickerSet final : public Jsonable {
  public:
   JsonStickerSet(const td_api::stickerSet *sticker_set, const Client *client)
       : sticker_set_(sticker_set), client_(client) {
@@ -2500,9 +2499,9 @@ class Client::JsonStickerSet : public Jsonable {
   const Client *client_;
 };
 
-class Client::TdOnOkCallback : public TdQueryCallback {
+class Client::TdOnOkCallback final : public TdQueryCallback {
  public:
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
       if (error->code_ != 401 && error->code_ != 406 && error->code_ != 500) {
@@ -2512,12 +2511,12 @@ class Client::TdOnOkCallback : public TdQueryCallback {
   }
 };
 
-class Client::TdOnAuthorizationCallback : public TdQueryCallback {
+class Client::TdOnAuthorizationCallback final : public TdQueryCallback {
  public:
   explicit TdOnAuthorizationCallback(Client *client) : client_(client) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     bool was_ready = client_->authorization_state_->get_id() != td_api::authorizationStateWaitPhoneNumber::ID;
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
@@ -2537,12 +2536,12 @@ class Client::TdOnAuthorizationCallback : public TdQueryCallback {
   Client *client_;
 };
 
-class Client::TdOnInitCallback : public TdQueryCallback {
+class Client::TdOnInitCallback final : public TdQueryCallback {
  public:
   explicit TdOnInitCallback(Client *client) : client_(client) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       LOG(WARNING) << "Failed to initialize due to " << td::oneline(to_string(result));
       client_->close();
@@ -2553,13 +2552,13 @@ class Client::TdOnInitCallback : public TdQueryCallback {
   Client *client_;
 };
 
-class Client::TdOnGetUserProfilePhotosCallback : public TdQueryCallback {
+class Client::TdOnGetUserProfilePhotosCallback final : public TdQueryCallback {
  public:
   TdOnGetUserProfilePhotosCallback(const Client *client, PromisedQueryPtr query)
       : client_(client), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -2574,12 +2573,12 @@ class Client::TdOnGetUserProfilePhotosCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnSendMessageCallback : public TdQueryCallback {
+class Client::TdOnSendMessageCallback final : public TdQueryCallback {
  public:
   TdOnSendMessageCallback(Client *client, PromisedQueryPtr query) : client_(client), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -2594,12 +2593,12 @@ class Client::TdOnSendMessageCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnSendMessageAlbumCallback : public TdQueryCallback {
+class Client::TdOnSendMessageAlbumCallback final : public TdQueryCallback {
  public:
   TdOnSendMessageAlbumCallback(Client *client, PromisedQueryPtr query) : client_(client), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -2617,7 +2616,7 @@ class Client::TdOnSendMessageAlbumCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnDeleteFailedToSendMessageCallback : public TdQueryCallback {
+class Client::TdOnDeleteFailedToSendMessageCallback final : public TdQueryCallback {
  public:
   TdOnDeleteFailedToSendMessageCallback(Client *client, int64 chat_id, int64 message_id)
       : client_(client)
@@ -2626,7 +2625,7 @@ class Client::TdOnDeleteFailedToSendMessageCallback : public TdQueryCallback {
       , old_chat_description_(client->get_chat_description(chat_id)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
       if (error->code_ != 401 && !client_->need_close_ && !client_->closing_ && !client_->logging_out_) {
@@ -2651,12 +2650,12 @@ class Client::TdOnDeleteFailedToSendMessageCallback : public TdQueryCallback {
   td::string old_chat_description_;
 };
 
-class Client::TdOnEditMessageCallback : public TdQueryCallback {
+class Client::TdOnEditMessageCallback final : public TdQueryCallback {
  public:
   TdOnEditMessageCallback(const Client *client, PromisedQueryPtr query) : client_(client), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -2679,12 +2678,12 @@ class Client::TdOnEditMessageCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnEditInlineMessageCallback : public TdQueryCallback {
+class Client::TdOnEditInlineMessageCallback final : public TdQueryCallback {
  public:
   explicit TdOnEditInlineMessageCallback(PromisedQueryPtr query) : query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -2697,13 +2696,13 @@ class Client::TdOnEditInlineMessageCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnStopPollCallback : public TdQueryCallback {
+class Client::TdOnStopPollCallback final : public TdQueryCallback {
  public:
   TdOnStopPollCallback(const Client *client, int64 chat_id, int64 message_id, PromisedQueryPtr query)
       : client_(client), chat_id_(chat_id), message_id_(message_id), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -2728,13 +2727,13 @@ class Client::TdOnStopPollCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnOkQueryCallback : public TdQueryCallback {
+class Client::TdOnOkQueryCallback final : public TdQueryCallback {
  public:
   explicit TdOnOkQueryCallback(PromisedQueryPtr query) : query_(std::move(query)) {
     CHECK(query_ != nullptr);
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -2748,13 +2747,13 @@ class Client::TdOnOkQueryCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnCheckUserCallback : public TdQueryCallback {
+class Client::TdOnCheckUserCallback final : public TdQueryCallback {
  public:
   TdOnCheckUserCallback(const Client *client, PromisedQueryPtr query, OnSuccess on_success)
       : client_(client), query_(std::move(query)), on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result), "user not found");
     }
@@ -2774,13 +2773,13 @@ class Client::TdOnCheckUserCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnCheckUserNoFailCallback : public TdQueryCallback {
+class Client::TdOnCheckUserNoFailCallback final : public TdQueryCallback {
  public:
   TdOnCheckUserNoFailCallback(PromisedQueryPtr query, OnSuccess on_success)
       : query_(std::move(query)), on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     on_success_(std::move(query_));
   }
 
@@ -2790,7 +2789,7 @@ class Client::TdOnCheckUserNoFailCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnCheckChatCallback : public TdQueryCallback {
+class Client::TdOnCheckChatCallback final : public TdQueryCallback {
  public:
   TdOnCheckChatCallback(const Client *client, bool only_supergroup, AccessRights access_rights, PromisedQueryPtr query,
                         OnSuccess on_success)
@@ -2801,7 +2800,7 @@ class Client::TdOnCheckChatCallback : public TdQueryCallback {
       , on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result), "chat not found");
     }
@@ -2827,13 +2826,13 @@ class Client::TdOnCheckChatCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnCheckChatNoFailCallback : public TdQueryCallback {
+class Client::TdOnCheckChatNoFailCallback final : public TdQueryCallback {
  public:
   TdOnCheckChatNoFailCallback(int64 chat_id, PromisedQueryPtr query, OnSuccess on_success)
       : chat_id_(chat_id), query_(std::move(query)), on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     on_success_(chat_id_, std::move(query_));
   }
 
@@ -2844,13 +2843,13 @@ class Client::TdOnCheckChatNoFailCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnSearchStickerSetCallback : public TdQueryCallback {
+class Client::TdOnSearchStickerSetCallback final : public TdQueryCallback {
  public:
   TdOnSearchStickerSetCallback(PromisedQueryPtr query, OnSuccess on_success)
       : query_(std::move(query)), on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result), "sticker set not found");
     }
@@ -2865,13 +2864,13 @@ class Client::TdOnSearchStickerSetCallback : public TdQueryCallback {
   OnSuccess on_success_;
 };
 
-class Client::TdOnResolveBotUsernameCallback : public TdQueryCallback {
+class Client::TdOnResolveBotUsernameCallback final : public TdQueryCallback {
  public:
   TdOnResolveBotUsernameCallback(Client *client, td::string username)
       : client_(client), username_(std::move(username)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return client_->on_resolve_bot_username(username_, 0);
     }
@@ -2898,7 +2897,7 @@ class Client::TdOnResolveBotUsernameCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnCheckMessageCallback : public TdQueryCallback {
+class Client::TdOnCheckMessageCallback final : public TdQueryCallback {
  public:
   TdOnCheckMessageCallback(Client *client, int64 chat_id, int64 message_id, bool allow_empty, Slice message_type,
                            PromisedQueryPtr query, OnSuccess on_success)
@@ -2911,7 +2910,7 @@ class Client::TdOnCheckMessageCallback : public TdQueryCallback {
       , on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
       if (error->code_ == 429) {
@@ -2941,13 +2940,13 @@ class Client::TdOnCheckMessageCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnCheckRemoteFileIdCallback : public TdQueryCallback {
+class Client::TdOnCheckRemoteFileIdCallback final : public TdQueryCallback {
  public:
   TdOnCheckRemoteFileIdCallback(PromisedQueryPtr query, OnSuccess on_success)
       : query_(std::move(query)), on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result), "invalid file_id");
     }
@@ -2962,13 +2961,13 @@ class Client::TdOnCheckRemoteFileIdCallback : public TdQueryCallback {
 };
 
 template <class OnSuccess>
-class Client::TdOnGetChatMemberCallback : public TdQueryCallback {
+class Client::TdOnGetChatMemberCallback final : public TdQueryCallback {
  public:
   TdOnGetChatMemberCallback(PromisedQueryPtr query, OnSuccess on_success)
       : query_(std::move(query)), on_success_(std::move(on_success)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result), "user not found");
     }
@@ -2982,12 +2981,12 @@ class Client::TdOnGetChatMemberCallback : public TdQueryCallback {
   OnSuccess on_success_;
 };
 
-class Client::TdOnDownloadFileCallback : public TdQueryCallback {
+class Client::TdOnDownloadFileCallback final : public TdQueryCallback {
  public:
   TdOnDownloadFileCallback(Client *client, int32 file_id) : client_(client), file_id_(file_id) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
       return client_->on_file_download(file_id_, Status::Error(error->code_, error->message_));
@@ -3004,9 +3003,9 @@ class Client::TdOnDownloadFileCallback : public TdQueryCallback {
   int32 file_id_;
 };
 
-class Client::TdOnCancelDownloadFileCallback : public TdQueryCallback {
+class Client::TdOnCancelDownloadFileCallback final : public TdQueryCallback {
  public:
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       LOG(ERROR) << "Failed to cancel download file";
       return;
@@ -3015,12 +3014,12 @@ class Client::TdOnCancelDownloadFileCallback : public TdQueryCallback {
   }
 };
 
-class Client::TdOnGetReplyMessageCallback : public TdQueryCallback {
+class Client::TdOnGetReplyMessageCallback final : public TdQueryCallback {
  public:
   TdOnGetReplyMessageCallback(Client *client, int64 chat_id) : client_(client), chat_id_(chat_id) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return client_->on_get_reply_message(chat_id_, nullptr);
     }
@@ -3034,12 +3033,12 @@ class Client::TdOnGetReplyMessageCallback : public TdQueryCallback {
   int64 chat_id_;
 };
 
-class Client::TdOnGetEditedMessageCallback : public TdQueryCallback {
+class Client::TdOnGetEditedMessageCallback final : public TdQueryCallback {
  public:
   explicit TdOnGetEditedMessageCallback(Client *client) : client_(client) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
       if (error->code_ == 429) {
@@ -3056,13 +3055,13 @@ class Client::TdOnGetEditedMessageCallback : public TdQueryCallback {
   Client *client_;
 };
 
-class Client::TdOnGetCallbackQueryMessageCallback : public TdQueryCallback {
+class Client::TdOnGetCallbackQueryMessageCallback final : public TdQueryCallback {
  public:
   TdOnGetCallbackQueryMessageCallback(Client *client, int64 user_id, int state)
       : client_(client), user_id_(user_id), state_(state) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
       if (error->code_ == 429) {
@@ -3081,7 +3080,7 @@ class Client::TdOnGetCallbackQueryMessageCallback : public TdQueryCallback {
   int state_;
 };
 
-class Client::TdOnGetStickerSetCallback : public TdQueryCallback {
+class Client::TdOnGetStickerSetCallback final : public TdQueryCallback {
  public:
   TdOnGetStickerSetCallback(Client *client, int64 set_id, int64 new_callback_query_user_id, int64 new_message_chat_id)
       : client_(client)
@@ -3090,7 +3089,7 @@ class Client::TdOnGetStickerSetCallback : public TdQueryCallback {
       , new_message_chat_id_(new_message_chat_id) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
       if (error->message_ != "STICKERSET_INVALID" && error->code_ != 401 && error->code_ != 500) {
@@ -3113,13 +3112,13 @@ class Client::TdOnGetStickerSetCallback : public TdQueryCallback {
   int64 new_message_chat_id_;
 };
 
-class Client::TdOnGetChatStickerSetCallback : public TdQueryCallback {
+class Client::TdOnGetChatStickerSetCallback final : public TdQueryCallback {
  public:
   TdOnGetChatStickerSetCallback(Client *client, int64 chat_id, int64 pinned_message_id, PromisedQueryPtr query)
       : client_(client), chat_id_(chat_id), pinned_message_id_(pinned_message_id), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       auto chat_info = client_->get_chat(chat_id_);
       CHECK(chat_info != nullptr);
@@ -3141,13 +3140,13 @@ class Client::TdOnGetChatStickerSetCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetChatPinnedMessageCallback : public TdQueryCallback {
+class Client::TdOnGetChatPinnedMessageCallback final : public TdQueryCallback {
  public:
   TdOnGetChatPinnedMessageCallback(Client *client, int64 chat_id, PromisedQueryPtr query)
       : client_(client), chat_id_(chat_id), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     int64 pinned_message_id = 0;
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
@@ -3187,13 +3186,13 @@ class Client::TdOnGetChatPinnedMessageCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetChatPinnedMessageToUnpinCallback : public TdQueryCallback {
+class Client::TdOnGetChatPinnedMessageToUnpinCallback final : public TdQueryCallback {
  public:
   TdOnGetChatPinnedMessageToUnpinCallback(Client *client, int64 chat_id, PromisedQueryPtr query)
       : client_(client), chat_id_(chat_id), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     int64 pinned_message_id = 0;
     if (result->get_id() == td_api::error::ID) {
       auto error = move_object_as<td_api::error>(result);
@@ -3220,12 +3219,12 @@ class Client::TdOnGetChatPinnedMessageToUnpinCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetMyCommandsCallback : public TdQueryCallback {
+class Client::TdOnGetMyCommandsCallback final : public TdQueryCallback {
  public:
   explicit TdOnGetMyCommandsCallback(PromisedQueryPtr query) : query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3240,13 +3239,13 @@ class Client::TdOnGetMyCommandsCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetChatFullInfoCallback : public TdQueryCallback {
+class Client::TdOnGetChatFullInfoCallback final : public TdQueryCallback {
  public:
   TdOnGetChatFullInfoCallback(Client *client, int64 chat_id, PromisedQueryPtr query)
       : client_(client), chat_id_(chat_id), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3263,13 +3262,13 @@ class Client::TdOnGetChatFullInfoCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetGroupMembersCallback : public TdQueryCallback {
+class Client::TdOnGetGroupMembersCallback final : public TdQueryCallback {
  public:
   TdOnGetGroupMembersCallback(const Client *client, bool administrators_only, PromisedQueryPtr query)
       : client_(client), administrators_only_(administrators_only), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3286,13 +3285,13 @@ class Client::TdOnGetGroupMembersCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetSupergroupMembersCallback : public TdQueryCallback {
+class Client::TdOnGetSupergroupMembersCallback final : public TdQueryCallback {
  public:
   TdOnGetSupergroupMembersCallback(const Client *client, Client::ChatType chat_type, PromisedQueryPtr query)
       : client_(client), chat_type_(chat_type), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3308,12 +3307,12 @@ class Client::TdOnGetSupergroupMembersCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetSupergroupMembersCountCallback : public TdQueryCallback {
+class Client::TdOnGetSupergroupMembersCountCallback final : public TdQueryCallback {
  public:
   explicit TdOnGetSupergroupMembersCountCallback(PromisedQueryPtr query) : query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3327,12 +3326,12 @@ class Client::TdOnGetSupergroupMembersCountCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnReplacePrimaryChatInviteLinkCallback : public TdQueryCallback {
+class Client::TdOnReplacePrimaryChatInviteLinkCallback final : public TdQueryCallback {
  public:
   explicit TdOnReplacePrimaryChatInviteLinkCallback(PromisedQueryPtr query) : query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3346,13 +3345,13 @@ class Client::TdOnReplacePrimaryChatInviteLinkCallback : public TdQueryCallback
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetChatInviteLinkCallback : public TdQueryCallback {
+class Client::TdOnGetChatInviteLinkCallback final : public TdQueryCallback {
  public:
   TdOnGetChatInviteLinkCallback(const Client *client, PromisedQueryPtr query)
       : client_(client), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3373,13 +3372,13 @@ class Client::TdOnGetChatInviteLinkCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnGetGameHighScoresCallback : public TdQueryCallback {
+class Client::TdOnGetGameHighScoresCallback final : public TdQueryCallback {
  public:
   TdOnGetGameHighScoresCallback(const Client *client, PromisedQueryPtr query)
       : client_(client), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3396,12 +3395,12 @@ class Client::TdOnGetGameHighScoresCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnReturnFileCallback : public TdQueryCallback {
+class Client::TdOnReturnFileCallback final : public TdQueryCallback {
  public:
   TdOnReturnFileCallback(const Client *client, PromisedQueryPtr query) : client_(client), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3416,13 +3415,13 @@ class Client::TdOnReturnFileCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnReturnStickerSetCallback : public TdQueryCallback {
+class Client::TdOnReturnStickerSetCallback final : public TdQueryCallback {
  public:
   TdOnReturnStickerSetCallback(Client *client, bool return_sticker_set, PromisedQueryPtr query)
       : client_(client), return_sticker_set_(return_sticker_set), query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3443,12 +3442,12 @@ class Client::TdOnReturnStickerSetCallback : public TdQueryCallback {
   PromisedQueryPtr query_;
 };
 
-class Client::TdOnSendCustomRequestCallback : public TdQueryCallback {
+class Client::TdOnSendCustomRequestCallback final : public TdQueryCallback {
  public:
   explicit TdOnSendCustomRequestCallback(PromisedQueryPtr query) : query_(std::move(query)) {
   }
 
-  void on_result(object_ptr<td_api::Object> result) override {
+  void on_result(object_ptr<td_api::Object> result) final {
     if (result->get_id() == td_api::error::ID) {
       return fail_query_with_error(std::move(query_), move_object_as<td_api::error>(result));
     }
@@ -3548,14 +3547,14 @@ void Client::start_up() {
   }
   dir_ = parameters_->working_directory_ + suff;
 
-  class TdCallback : public td::TdCallback {
+  class TdCallback final : public td::TdCallback {
    public:
     explicit TdCallback(td::ActorId<Client> client) : client_(std::move(client)) {
     }
-    void on_result(td::uint64 id, object_ptr<td_api::Object> result) override {
+    void on_result(td::uint64 id, object_ptr<td_api::Object> result) final {
       send_closure_later(client_, &Client::on_result, id, std::move(result));
     }
-    void on_error(td::uint64 id, object_ptr<td_api::error> result) override {
+    void on_error(td::uint64 id, object_ptr<td_api::error> result) final {
       send_closure_later(client_, &Client::on_result, id, std::move(result));
     }
 
@@ -4603,7 +4602,7 @@ void Client::on_closed() {
   if (logging_out_) {
     parameters_->shared_data_->webhook_db_->erase(bot_token_with_dc_);
 
-    class RmWorker : public td::Actor {
+    class RmWorker final : public td::Actor {
      public:
       RmWorker(td::string dir, td::ActorId<Client> parent) : dir_(std::move(dir)), parent_(std::move(parent)) {
       }
@@ -4612,13 +4611,13 @@ void Client::on_closed() {
       td::string dir_;
       td::ActorId<Client> parent_;
 
-      void start_up() override {
+      void start_up() final {
         CHECK(dir_.size() >= 24);
         CHECK(dir_.back() == TD_DIR_SLASH);
         td::rmrf(dir_).ignore();
         stop();
       }
-      void tear_down() override {
+      void tear_down() final {
         send_closure(parent_, &Client::finish_closing);
       }
     };
@@ -8287,7 +8286,7 @@ void Client::fail_query_conflict(Slice message, PromisedQueryPtr &&query) {
   }
 }
 
-class Client::JsonUpdates : public Jsonable {
+class Client::JsonUpdates final : public Jsonable {
  public:
   explicit JsonUpdates(td::Span<td::TQueue::Event> updates) : updates_(updates) {
   }
@@ -8797,11 +8796,11 @@ bool Client::update_allowed_update_types(const Query *query) {
 }
 
 template <class T>
-class UpdateJsonable : public td::VirtuallyJsonable {
+class UpdateJsonable final : public td::VirtuallyJsonable {
  public:
   explicit UpdateJsonable(const T &update) : update(update) {
   }
-  void store(JsonValueScope *scope) const override {
+  void store(JsonValueScope *scope) const final {
     *scope << update;
   }
 
@@ -9760,7 +9759,7 @@ td::int64 Client::as_tdlib_message_id(int32 message_id) {
 }
 
 td::int32 Client::as_client_message_id(int64 message_id) {
-  int32 result = static_cast<int32>(message_id >> 20);
+  auto result = static_cast<int32>(message_id >> 20);
   CHECK(as_tdlib_message_id(result) == message_id);
   return result;
 }
diff --git a/telegram-bot-api/Client.h b/telegram-bot-api/Client.h
index fee9aad..3a9c638 100644
--- a/telegram-bot-api/Client.h
+++ b/telegram-bot-api/Client.h
@@ -11,6 +11,7 @@
 #include "telegram-bot-api/WebhookActor.h"
 
 #include "td/telegram/ClientActor.h"
+#include "td/telegram/td_api.h"
 
 #include "td/actor/actor.h"
 #include "td/actor/PromiseFuture.h"
@@ -35,12 +36,12 @@ struct ClientParameters;
 
 namespace td_api = td::td_api;
 
-class Client : public WebhookActor::Callback {
+class Client final : public WebhookActor::Callback {
  public:
   Client(td::ActorShared<> parent, const td::string &bot_token, bool is_test_dc, td::int64 tqueue_id,
          std::shared_ptr<const ClientParameters> parameters, td::ActorId<BotStatActor> stat_actor);
 
-  void send(PromisedQueryPtr query) override;
+  void send(PromisedQueryPtr query) final;
 
   void close();
 
@@ -519,11 +520,11 @@ class Client : public WebhookActor::Callback {
   Status process_get_webhook_info_query(PromisedQueryPtr &query);
   Status process_get_file_query(PromisedQueryPtr &query);
 
-  void webhook_verified(td::string cached_ip_address) override;
-  void webhook_success() override;
-  void webhook_error(Status status) override;
-  void webhook_closed(Status status) override;
-  void hangup_shared() override;
+  void webhook_verified(td::string cached_ip_address) final;
+  void webhook_success() final;
+  void webhook_error(Status status) final;
+  void webhook_closed(Status status) final;
+  void hangup_shared() final;
   int32 get_webhook_max_connections(const Query *query) const;
   static bool get_webhook_fix_ip_address(const Query *query);
   void do_set_webhook(PromisedQueryPtr query, bool was_deleted);
@@ -562,13 +563,13 @@ class Client : public WebhookActor::Callback {
 
   void long_poll_wakeup(bool force_flag);
 
-  void start_up() override;
+  void start_up() final;
 
-  void raw_event(const td::Event::Raw &event) override;
+  void raw_event(const td::Event::Raw &event) final;
 
-  void loop() override;
+  void loop() final;
 
-  void timeout_expired() override;
+  void timeout_expired() final;
 
   struct UserInfo {
     enum class Type { Regular, Deleted, Bot, Unknown };
diff --git a/telegram-bot-api/ClientManager.cpp b/telegram-bot-api/ClientManager.cpp
index 09a905f..f0f023d 100644
--- a/telegram-bot-api/ClientManager.cpp
+++ b/telegram-bot-api/ClientManager.cpp
@@ -11,6 +11,7 @@
 #include "telegram-bot-api/WebhookActor.h"
 
 #include "td/telegram/ClientActor.h"
+#include "td/telegram/td_api.h"
 
 #include "td/db/binlog/Binlog.h"
 #include "td/db/binlog/ConcurrentBinlog.h"
@@ -104,7 +105,7 @@ void ClientManager::send(PromisedQueryPtr query) {
         flood_control.add_limit(60, 20);        // 20 in a minute
         flood_control.add_limit(60 * 60, 600);  // 600 in an hour
       }
-      td::uint32 now = static_cast<td::uint32>(td::Time::now());
+      auto now = static_cast<td::uint32>(td::Time::now());
       td::uint32 wakeup_at = flood_control.get_wakeup_at();
       if (wakeup_at > now) {
         LOG(INFO) << "Failed to create Client from IP address " << ip_address;
diff --git a/telegram-bot-api/ClientManager.h b/telegram-bot-api/ClientManager.h
index e376490..5720d98 100644
--- a/telegram-bot-api/ClientManager.h
+++ b/telegram-bot-api/ClientManager.h
@@ -73,9 +73,9 @@ class ClientManager final : public td::Actor {
   static PromisedQueryPtr get_webhook_restore_query(td::Slice token, td::Slice webhook_info,
                                                     std::shared_ptr<SharedData> shared_data);
 
-  void start_up() override;
-  void raw_event(const td::Event::Raw &event) override;
-  void hangup_shared() override;
+  void start_up() final;
+  void raw_event(const td::Event::Raw &event) final;
+  void hangup_shared() final;
   void close_db();
   void finish_close();
 };
diff --git a/telegram-bot-api/ClientParameters.h b/telegram-bot-api/ClientParameters.h
index 79607f7..455e72f 100644
--- a/telegram-bot-api/ClientParameters.h
+++ b/telegram-bot-api/ClientParameters.h
@@ -6,13 +6,13 @@
 //
 #pragma once
 
-#include "td/actor/actor.h"
-
 #include "td/db/KeyValueSyncInterface.h"
 #include "td/db/TQueue.h"
 
 #include "td/net/GetHostByNameActor.h"
 
+#include "td/actor/actor.h"
+
 #include "td/utils/common.h"
 #include "td/utils/List.h"
 #include "td/utils/port/IPAddress.h"
diff --git a/telegram-bot-api/HttpConnection.h b/telegram-bot-api/HttpConnection.h
index a4b1160..d631244 100644
--- a/telegram-bot-api/HttpConnection.h
+++ b/telegram-bot-api/HttpConnection.h
@@ -9,12 +9,12 @@
 #include "telegram-bot-api/ClientManager.h"
 #include "telegram-bot-api/Query.h"
 
-#include "td/actor/actor.h"
-#include "td/actor/PromiseFuture.h"
-
 #include "td/net/HttpInboundConnection.h"
 #include "td/net/HttpQuery.h"
 
+#include "td/actor/actor.h"
+#include "td/actor/PromiseFuture.h"
+
 #include "td/utils/buffer.h"
 #include "td/utils/Slice.h"
 
@@ -24,15 +24,15 @@ namespace telegram_bot_api {
 
 struct SharedData;
 
-class HttpConnection : public td::HttpInboundConnection::Callback {
+class HttpConnection final : public td::HttpInboundConnection::Callback {
  public:
   explicit HttpConnection(td::ActorId<ClientManager> client_manager, std::shared_ptr<SharedData> shared_data)
       : client_manager_(client_manager), shared_data_(std::move(shared_data)) {
   }
 
-  void handle(td::unique_ptr<td::HttpQuery> http_query, td::ActorOwn<td::HttpInboundConnection> connection) override;
+  void handle(td::unique_ptr<td::HttpQuery> http_query, td::ActorOwn<td::HttpInboundConnection> connection) final;
 
-  void wakeup() override;
+  void wakeup() final;
 
  private:
   td::FutureActor<td::unique_ptr<Query>> result_;
@@ -40,7 +40,7 @@ class HttpConnection : public td::HttpInboundConnection::Callback {
   td::ActorOwn<td::HttpInboundConnection> connection_;
   std::shared_ptr<SharedData> shared_data_;
 
-  void hangup() override {
+  void hangup() final {
     connection_.release();
     stop();
   }
diff --git a/telegram-bot-api/HttpServer.h b/telegram-bot-api/HttpServer.h
index b500bab..f7d0009 100644
--- a/telegram-bot-api/HttpServer.h
+++ b/telegram-bot-api/HttpServer.h
@@ -6,11 +6,11 @@
 //
 #pragma once
 
-#include "td/actor/actor.h"
-
 #include "td/net/HttpInboundConnection.h"
 #include "td/net/TcpListener.h"
 
+#include "td/actor/actor.h"
+
 #include "td/utils/BufferedFd.h"
 #include "td/utils/FloodControlFast.h"
 #include "td/utils/format.h"
@@ -23,7 +23,7 @@
 
 namespace telegram_bot_api {
 
-class HttpServer : public td::TcpListener::Callback {
+class HttpServer final : public td::TcpListener::Callback {
  public:
   HttpServer(td::string ip_address, int port,
              std::function<td::ActorOwn<td::HttpInboundConnection::Callback>()> creator)
@@ -39,7 +39,7 @@ class HttpServer : public td::TcpListener::Callback {
   td::ActorOwn<td::TcpListener> listener_;
   td::FloodControlFast flood_control_;
 
-  void start_up() override {
+  void start_up() final {
     auto now = td::Time::now();
     auto wakeup_at = flood_control_.get_wakeup_at();
     if (wakeup_at > now) {
@@ -53,13 +53,13 @@ class HttpServer : public td::TcpListener::Callback {
         actor_shared(this, 1), ip_address_);
   }
 
-  void hangup_shared() override {
+  void hangup_shared() final {
     LOG(ERROR) << "TCP listener was closed";
     listener_.release();
     yield();
   }
 
-  void accept(td::SocketFd fd) override {
+  void accept(td::SocketFd fd) final {
     auto scheduler_count = td::Scheduler::instance()->sched_count();
     auto scheduler_id = scheduler_count - 1;
     if (scheduler_id > 0) {
@@ -70,7 +70,7 @@ class HttpServer : public td::TcpListener::Callback {
         .release();
   }
 
-  void loop() override {
+  void loop() final {
     if (listener_.empty()) {
       start_up();
     }
diff --git a/telegram-bot-api/HttpStatConnection.h b/telegram-bot-api/HttpStatConnection.h
index 5ef7db9..614f5ca 100644
--- a/telegram-bot-api/HttpStatConnection.h
+++ b/telegram-bot-api/HttpStatConnection.h
@@ -8,30 +8,30 @@
 
 #include "telegram-bot-api/ClientManager.h"
 
-#include "td/actor/actor.h"
-#include "td/actor/PromiseFuture.h"
-
 #include "td/net/HttpInboundConnection.h"
 #include "td/net/HttpQuery.h"
 
+#include "td/actor/actor.h"
+#include "td/actor/PromiseFuture.h"
+
 #include "td/utils/buffer.h"
 
 namespace telegram_bot_api {
 
-class HttpStatConnection : public td::HttpInboundConnection::Callback {
+class HttpStatConnection final : public td::HttpInboundConnection::Callback {
  public:
   explicit HttpStatConnection(td::ActorId<ClientManager> client_manager) : client_manager_(client_manager) {
   }
-  void handle(td::unique_ptr<td::HttpQuery> http_query, td::ActorOwn<td::HttpInboundConnection> connection) override;
+  void handle(td::unique_ptr<td::HttpQuery> http_query, td::ActorOwn<td::HttpInboundConnection> connection) final;
 
-  void wakeup() override;
+  void wakeup() final;
 
  private:
   td::FutureActor<td::BufferSlice> result_;
   td::ActorId<ClientManager> client_manager_;
   td::ActorOwn<td::HttpInboundConnection> connection_;
 
-  void hangup() override {
+  void hangup() final {
     connection_.release();
     stop();
   }
diff --git a/telegram-bot-api/Query.h b/telegram-bot-api/Query.h
index 92cb9bb..f5d15f8 100644
--- a/telegram-bot-api/Query.h
+++ b/telegram-bot-api/Query.h
@@ -8,11 +8,11 @@
 
 #include "telegram-bot-api/ClientParameters.h"
 
+#include "td/net/HttpFile.h"
+
 #include "td/actor/actor.h"
 #include "td/actor/PromiseFuture.h"
 
-#include "td/net/HttpFile.h"
-
 #include "td/utils/buffer.h"
 #include "td/utils/common.h"
 #include "td/utils/JsonBuilder.h"
@@ -30,7 +30,7 @@ namespace telegram_bot_api {
 
 class BotStatActor;
 
-class Query : public td::ListNode {
+class Query final : public td::ListNode {
  public:
   enum class State : td::int8 { Query, OK, Error };
 
@@ -166,7 +166,7 @@ td::StringBuilder &operator<<(td::StringBuilder &sb, const Query &query);
 // https://stackoverflow.com/questions/26947704/implicit-conversion-failure-from-initializer-list
 extern std::unordered_map<td::string, std::unique_ptr<td::VirtuallyJsonable>> empty_parameters;
 
-class JsonParameters : public td::Jsonable {
+class JsonParameters final : public td::Jsonable {
  public:
   explicit JsonParameters(const std::unordered_map<td::string, std::unique_ptr<td::VirtuallyJsonable>> &parameters)
       : parameters_(parameters) {
@@ -184,7 +184,7 @@ class JsonParameters : public td::Jsonable {
 };
 
 template <class T>
-class JsonQueryOk : public td::Jsonable {
+class JsonQueryOk final : public td::Jsonable {
  public:
   JsonQueryOk(const T &result, td::Slice description) : result_(result), description_(description) {
   }
@@ -202,7 +202,7 @@ class JsonQueryOk : public td::Jsonable {
   td::Slice description_;
 };
 
-class JsonQueryError : public td::Jsonable {
+class JsonQueryError final : public td::Jsonable {
  public:
   JsonQueryError(
       int error_code, td::Slice description,
diff --git a/telegram-bot-api/Stats.h b/telegram-bot-api/Stats.h
index 06e6606..3b317fc 100644
--- a/telegram-bot-api/Stats.h
+++ b/telegram-bot-api/Stats.h
@@ -156,7 +156,7 @@ class BotStatActor final : public td::Actor {
   BotStatActor(const BotStatActor &) = delete;
   BotStatActor &operator=(const BotStatActor &other) = delete;
   BotStatActor(BotStatActor &&) = default;
-  BotStatActor &operator=(BotStatActor &&other) {
+  BotStatActor &operator=(BotStatActor &&other) noexcept {
     if (!empty()) {
       do_stop();
     }
@@ -165,7 +165,7 @@ class BotStatActor final : public td::Actor {
     parent_ = other.parent_;
     return *this;
   }
-  ~BotStatActor() override = default;
+  ~BotStatActor() final = default;
 
   template <class EventT>
   void add_event(const EventT &event, double now) {
diff --git a/telegram-bot-api/WebhookActor.cpp b/telegram-bot-api/WebhookActor.cpp
index ce51f88..1d7a559 100644
--- a/telegram-bot-api/WebhookActor.cpp
+++ b/telegram-bot-api/WebhookActor.cpp
@@ -152,11 +152,11 @@ td::Status WebhookActor::create_connection() {
     }
 
     VLOG(webhook) << "Create connection through proxy " << parameters_->webhook_proxy_ip_address_;
-    class Callback : public td::TransparentProxy::Callback {
+    class Callback final : public td::TransparentProxy::Callback {
      public:
       Callback(td::ActorId<WebhookActor> actor, td::int64 id) : actor_(actor), id_(id) {
       }
-      void set_result(td::Result<td::BufferedFd<td::SocketFd>> result) override {
+      void set_result(td::Result<td::BufferedFd<td::SocketFd>> result) final {
         send_closure(std::move(actor_), &WebhookActor::on_socket_ready_async, std::move(result), id_);
         CHECK(actor_.empty());
       }
@@ -169,7 +169,7 @@ td::Status WebhookActor::create_connection() {
           send_closure(std::move(actor_), &WebhookActor::on_socket_ready_async, td::Status::Error("Canceled"), id_);
         }
       }
-      void on_connected() override {
+      void on_connected() final {
         // nothing to do
       }
 
diff --git a/telegram-bot-api/WebhookActor.h b/telegram-bot-api/WebhookActor.h
index fa98ddb..6067d73 100644
--- a/telegram-bot-api/WebhookActor.h
+++ b/telegram-bot-api/WebhookActor.h
@@ -41,7 +41,7 @@ namespace telegram_bot_api {
 
 struct ClientParameters;
 
-class WebhookActor : public td::HttpOutboundConnection::Callback {
+class WebhookActor final : public td::HttpOutboundConnection::Callback {
  public:
   class Callback : public td::Actor {
    public:
@@ -139,7 +139,7 @@ class WebhookActor : public td::HttpOutboundConnection::Callback {
   double next_ip_address_resolve_time_ = 0;
   td::FutureActor<td::IPAddress> future_ip_address_;
 
-  class Connection : public td::ListNode {
+  class Connection final : public td::ListNode {
    public:
     Connection() = default;
     Connection(const Connection &) = delete;
@@ -190,26 +190,26 @@ class WebhookActor : public td::HttpOutboundConnection::Callback {
   td::Status send_update() TD_WARN_UNUSED_RESULT;
   void send_updates();
 
-  void loop() override;
-  void handle(td::unique_ptr<td::HttpQuery> response) override;
+  void loop() final;
+  void handle(td::unique_ptr<td::HttpQuery> response) final;
 
-  void hangup_shared() override;
+  void hangup_shared() final;
 
-  void hangup() override;
+  void hangup() final;
 
-  void tear_down() override;
+  void tear_down() final;
 
-  void start_up() override;
+  void start_up() final;
 
   bool check_ip_address(const td::IPAddress &addr) const;
 
   void on_error(td::Status status);
-  void on_connection_error(td::Status error) override;
+  void on_connection_error(td::Status error) final;
   void on_webhook_error(td::Slice error);
   void on_webhook_verified();
 };
 
-class JsonUpdate : public td::Jsonable {
+class JsonUpdate final : public td::Jsonable {
  public:
   JsonUpdate(td::int32 id, td::Slice update) : id_(id), update_(update) {
   }
diff --git a/telegram-bot-api/telegram-bot-api.cpp b/telegram-bot-api/telegram-bot-api.cpp
index cf423ee..e42390d 100644
--- a/telegram-bot-api/telegram-bot-api.cpp
+++ b/telegram-bot-api/telegram-bot-api.cpp
@@ -310,16 +310,16 @@ int main(int argc, char *argv[]) {
   options.add_checked_option('c', "max-connections", "maximum number of open file descriptors",
                              td::OptionParser::parse_integer(max_connections));
 
-  options.add_checked_option(
-      '\0', "proxy", PSLICE() << "HTTP proxy server for outgoing webhook requests in the format http://host:port",
-      [&](td::Slice address) {
-        if (td::begins_with(address, "http://")) {
-          address.remove_prefix(7);
-        } else if (td::begins_with(address, "https://")) {
-          address.remove_prefix(8);
-        }
-        return parameters->webhook_proxy_ip_address_.init_host_port(address.str());
-      });
+  options.add_checked_option('\0', "proxy",
+                             "HTTP proxy server for outgoing webhook requests in the format http://host:port",
+                             [&](td::Slice address) {
+                               if (td::begins_with(address, "http://")) {
+                                 address.remove_prefix(7);
+                               } else if (td::begins_with(address, "https://")) {
+                                 address.remove_prefix(8);
+                               }
+                               return parameters->webhook_proxy_ip_address_.init_host_port(address.str());
+                             });
   options.add_check([&] {
     if (parameters->api_id_ <= 0 || parameters->api_hash_.empty()) {
       return td::Status::Error("You must provide valid api-id and api-hash obtained at https://my.telegram.org");