diff --git a/td/telegram/AccessRights.h b/td/telegram/AccessRights.h
index fd0833ea..8beece72 100644
--- a/td/telegram/AccessRights.h
+++ b/td/telegram/AccessRights.h
@@ -8,6 +8,6 @@
 
 namespace td {
 
-enum class AccessRights { Read, Edit, Write };
+enum class AccessRights : int32 { Read, Edit, Write };
 
 }  // namespace td
diff --git a/td/telegram/AuthManager.h b/td/telegram/AuthManager.h
index 638be16b..1cdc9fe9 100644
--- a/td/telegram/AuthManager.h
+++ b/td/telegram/AuthManager.h
@@ -96,7 +96,7 @@ class SendCodeHelper {
 
 class PhoneNumberManager : public NetActor {
  public:
-  enum class Type { ChangePhone, VerifyPhone, ConfirmPhone };
+  enum class Type : int32 { ChangePhone, VerifyPhone, ConfirmPhone };
   PhoneNumberManager(Type type, ActorShared<> parent);
   void get_state(uint64 query_id);
 
@@ -108,8 +108,8 @@ class PhoneNumberManager : public NetActor {
  private:
   Type type_;
 
-  enum class State { Ok, WaitCode } state_ = State::Ok;
-  enum class NetQueryType { None, SendCode, CheckCode };
+  enum class State : int32 { Ok, WaitCode } state_ = State::Ok;
+  enum class NetQueryType : int32 { None, SendCode, CheckCode };
 
   ActorShared<> parent_;
   uint64 query_id_ = 0;
@@ -173,7 +173,7 @@ class AuthManager : public NetActor {
     LoggingOut,
     Closing
   } state_ = State::None;
-  enum class NetQueryType {
+  enum class NetQueryType : int32 {
     None,
     SignIn,
     SignUp,
diff --git a/td/telegram/CallActor.h b/td/telegram/CallActor.h
index 02960bb3..492f38a5 100644
--- a/td/telegram/CallActor.h
+++ b/td/telegram/CallActor.h
@@ -51,7 +51,7 @@ struct CallConnection {
 };
 
 struct CallState {
-  enum class Type { Empty, Pending, ExchangingKey, Ready, HangingUp, Discarded, Error } type{Type::Empty};
+  enum class Type : int32 { Empty, Pending, ExchangingKey, Ready, HangingUp, Discarded, Error } type{Type::Empty};
 
   CallProtocol protocol;
   std::vector<CallConnection> connections;
@@ -97,7 +97,7 @@ class CallActor : public NetQueryCallback {
   int32 duration_{0};
   int64 connection_id_{0};
 
-  enum class State {
+  enum class State : int32 {
     Empty,
     SendRequestQuery,
     WaitRequestResult,
diff --git a/td/telegram/ContactsManager.h b/td/telegram/ContactsManager.h
index ccfae6b1..8d1d6218 100644
--- a/td/telegram/ContactsManager.h
+++ b/td/telegram/ContactsManager.h
@@ -51,9 +51,9 @@ struct BotData {
   bool need_location;
 };
 
-enum class ChannelType { Broadcast, Megagroup, Unknown };
+enum class ChannelType : uint8 { Broadcast, Megagroup, Unknown };
 
-enum class CheckDialogUsernameResult { Ok, Invalid, Occupied, PublicDialogsTooMuch, PublicGroupsUnavailable };
+enum class CheckDialogUsernameResult : uint8 { Ok, Invalid, Occupied, PublicDialogsTooMuch, PublicGroupsUnavailable };
 
 class ContactsManager : public Actor {
  public:
diff --git a/td/telegram/DeviceTokenManager.h b/td/telegram/DeviceTokenManager.h
index 8858f85d..4d204d31 100644
--- a/td/telegram/DeviceTokenManager.h
+++ b/td/telegram/DeviceTokenManager.h
@@ -47,7 +47,7 @@ class DeviceTokenManager : public NetQueryCallback {
     SIZE
   };
   struct TokenInfo {
-    enum class State { Sync, Unregister, Register };
+    enum class State : int32 { Sync, Unregister, Register };
     State state = State::Sync;
     string token;
     uint64 net_query_id = 0;
diff --git a/td/telegram/DialogId.h b/td/telegram/DialogId.h
index ac11ced8..1ad37b25 100644
--- a/td/telegram/DialogId.h
+++ b/td/telegram/DialogId.h
@@ -21,7 +21,7 @@
 
 namespace td {
 
-enum class DialogType { None, User, Chat, Channel, SecretChat };
+enum class DialogType : int32 { None, User, Chat, Channel, SecretChat };
 
 class DialogId {
   static constexpr int64 MIN_SECRET_ID = -2002147483648ll;
diff --git a/td/telegram/DialogParticipant.cpp b/td/telegram/DialogParticipant.cpp
index 556d4bde..016509a3 100644
--- a/td/telegram/DialogParticipant.cpp
+++ b/td/telegram/DialogParticipant.cpp
@@ -374,17 +374,17 @@ DialogParticipantStatus get_dialog_participant_status(
 tl_object_ptr<telegram_api::ChannelParticipantsFilter>
 ChannelParticipantsFilter::get_input_channel_participants_filter() const {
   switch (type) {
-    case Recent:
+    case Type::Recent:
       return make_tl_object<telegram_api::channelParticipantsRecent>();
-    case Administrators:
+    case Type::Administrators:
       return make_tl_object<telegram_api::channelParticipantsAdmins>();
-    case Search:
+    case Type::Search:
       return make_tl_object<telegram_api::channelParticipantsSearch>(query);
-    case Restricted:
+    case Type::Restricted:
       return make_tl_object<telegram_api::channelParticipantsBanned>(query);
-    case Banned:
+    case Type::Banned:
       return make_tl_object<telegram_api::channelParticipantsKicked>(query);
-    case Bots:
+    case Type::Bots:
       return make_tl_object<telegram_api::channelParticipantsBots>();
     default:
       UNREACHABLE();
@@ -394,34 +394,34 @@ ChannelParticipantsFilter::get_input_channel_participants_filter() const {
 
 ChannelParticipantsFilter::ChannelParticipantsFilter(const tl_object_ptr<td_api::SupergroupMembersFilter> &filter) {
   if (filter == nullptr) {
-    type = Recent;
+    type = Type::Recent;
     return;
   }
   switch (filter->get_id()) {
     case td_api::supergroupMembersFilterRecent::ID:
-      type = Recent;
+      type = Type::Recent;
       return;
     case td_api::supergroupMembersFilterAdministrators::ID:
-      type = Administrators;
+      type = Type::Administrators;
       return;
     case td_api::supergroupMembersFilterSearch::ID:
-      type = Search;
+      type = Type::Search;
       query = static_cast<const td_api::supergroupMembersFilterSearch *>(filter.get())->query_;
       return;
     case td_api::supergroupMembersFilterRestricted::ID:
-      type = Restricted;
+      type = Type::Restricted;
       query = static_cast<const td_api::supergroupMembersFilterRestricted *>(filter.get())->query_;
       return;
     case td_api::supergroupMembersFilterBanned::ID:
-      type = Banned;
+      type = Type::Banned;
       query = static_cast<const td_api::supergroupMembersFilterBanned *>(filter.get())->query_;
       return;
     case td_api::supergroupMembersFilterBots::ID:
-      type = Bots;
+      type = Type::Bots;
       return;
     default:
       UNREACHABLE();
-      type = Recent;
+      type = Type::Recent;
   }
 }
 
diff --git a/td/telegram/DialogParticipant.h b/td/telegram/DialogParticipant.h
index ab4c36a3..5bb3d22b 100644
--- a/td/telegram/DialogParticipant.h
+++ b/td/telegram/DialogParticipant.h
@@ -52,7 +52,7 @@ class DialogParticipantStatus {
                                                   CAN_SEND_ANIMATIONS | CAN_SEND_GAMES | CAN_USE_INLINE_BOTS |
                                                   CAN_ADD_WEB_PAGE_PREVIEWS;
 
-  enum class Type { Creator, Administrator, Member, Restricted, Left, Banned };
+  enum class Type : int32 { Creator, Administrator, Member, Restricted, Left, Banned };
   // all fields are logically const, but should be updated in update_restrictions()
   mutable Type type_;
   mutable uint32 flags_;
@@ -239,7 +239,7 @@ struct DialogParticipant {
 };
 
 class ChannelParticipantsFilter {
-  enum { Recent, Administrators, Search, Restricted, Banned, Bots } type;
+  enum class Type : int32 { Recent, Administrators, Search, Restricted, Banned, Bots } type;
   string query;
 
  public:
@@ -248,7 +248,7 @@ class ChannelParticipantsFilter {
   tl_object_ptr<telegram_api::ChannelParticipantsFilter> get_input_channel_participants_filter() const;
 
   bool is_administrators() const {
-    return type == Administrators;
+    return type == Type::Administrators;
   }
 };
 
diff --git a/td/telegram/DocumentsManager.h b/td/telegram/DocumentsManager.h
index edbc02d6..e515f2f0 100644
--- a/td/telegram/DocumentsManager.h
+++ b/td/telegram/DocumentsManager.h
@@ -32,7 +32,7 @@ class DocumentsManager {
  public:
   explicit DocumentsManager(Td *td);
 
-  enum class DocumentType { Unknown, Animation, Audio, General, Sticker, Video, VideoNote, VoiceNote };
+  enum class DocumentType : int32 { Unknown, Animation, Audio, General, Sticker, Video, VideoNote, VoiceNote };
 
   class RemoteDocument {
    public:
diff --git a/td/telegram/MessagesDb.h b/td/telegram/MessagesDb.h
index 86843dd5..e3e3e1f3 100644
--- a/td/telegram/MessagesDb.h
+++ b/td/telegram/MessagesDb.h
@@ -22,7 +22,7 @@
 
 namespace td {
 // append only before Size
-enum class SearchMessagesFilter {
+enum class SearchMessagesFilter : int32 {
   Empty,
   Animation,
   Audio,
diff --git a/td/telegram/MessagesManager.h b/td/telegram/MessagesManager.h
index 128ac01e..22a7de52 100644
--- a/td/telegram/MessagesManager.h
+++ b/td/telegram/MessagesManager.h
@@ -705,7 +705,7 @@ class DialogNotificationSettings {
   }
 };
 
-enum class NotificationSettingsScope { Private, Group };
+enum class NotificationSettingsScope : int32 { Private, Group };
 
 class ScopeNotificationSettings {
  public:
@@ -2663,7 +2663,7 @@ class MessagesManager : public Actor {
   KHeap<double> ttl_heap_;
   Slot ttl_slot_;
 
-  enum YieldType { None, Ttl, TtlDb };  // None must be first
+  enum YieldType : int32 { None, Ttl, TtlDb };  // None must be first
   int32 ttl_db_expire_from_;
   int32 ttl_db_expire_till_;
   bool ttl_db_has_query_;
diff --git a/td/telegram/PrivacyManager.h b/td/telegram/PrivacyManager.h
index 820e435a..d8f3d6f0 100644
--- a/td/telegram/PrivacyManager.h
+++ b/td/telegram/PrivacyManager.h
@@ -67,7 +67,7 @@ class PrivacyManager : public NetQueryCallback {
     }
 
    private:
-    enum class Type {
+    enum class Type : int32 {
       AllowContacts,
       AllowAll,
       AllowUsers,
diff --git a/td/telegram/SecretChatActor.h b/td/telegram/SecretChatActor.h
index 7c8e04cc..d63459c1 100644
--- a/td/telegram/SecretChatActor.h
+++ b/td/telegram/SecretChatActor.h
@@ -136,8 +136,8 @@ class SecretChatActor : public NetQueryCallback {
   void binlog_replay_finish();
 
  private:
-  enum class State { Empty, SendRequest, SendAccept, WaitRequestResponse, WaitAcceptResponse, Ready, Closed };
-  enum { MAX_RESEND_COUNT = 1000 };
+  enum class State : int32 { Empty, SendRequest, SendAccept, WaitRequestResponse, WaitAcceptResponse, Ready, Closed };
+  static constexpr int32 MAX_RESEND_COUNT = 1000;
 
   // We have git state that should be shynchronized with db.
   // It is splitted into several parts because:
@@ -198,7 +198,7 @@ class SecretChatActor : public NetQueryCallback {
       ttl = parser.fetch_int();
       bool has_flags = (his_layer & HAS_FLAGS) != 0;
       if (has_flags) {
-        his_layer &= ~HAS_FLAGS;
+        his_layer &= static_cast<int32>(~HAS_FLAGS);
         my_layer = parser.fetch_int();
         // for future usage
         BEGIN_PARSE_FLAGS();
@@ -206,7 +206,7 @@ class SecretChatActor : public NetQueryCallback {
       }
     }
 
-    enum { HAS_FLAGS = 1 << 31 };
+    static constexpr uint32 HAS_FLAGS = 1u << 31;
   };
 
   // PfsAction
@@ -576,7 +576,7 @@ class SecretChatActor : public NetQueryCallback {
   int32 last_read_history_date_ = -1;
   Promise<Unit> read_history_promise_;
 
-  enum SendFlag {
+  enum SendFlag : int32 {
     None = 0,
     External = 1,
     Push = 2,
diff --git a/td/telegram/SecureManager.h b/td/telegram/SecureManager.h
index 4d4b331a..02168295 100644
--- a/td/telegram/SecureManager.h
+++ b/td/telegram/SecureManager.h
@@ -91,7 +91,7 @@ class SetSecureValue : public NetQueryCallback {
   class UploadCallback;
   std::shared_ptr<UploadCallback> upload_callback_;
 
-  enum class State { WaitSecret, WaitSetValue } state_ = State::WaitSecret;
+  enum class State : int32 { WaitSecret, WaitSetValue } state_ = State::WaitSecret;
 
   class UploadCallback : public FileManager::UploadCallback {
    public:
diff --git a/td/telegram/SequenceDispatcher.h b/td/telegram/SequenceDispatcher.h
index 5ce46068..dbfbef90 100644
--- a/td/telegram/SequenceDispatcher.h
+++ b/td/telegram/SequenceDispatcher.h
@@ -30,7 +30,7 @@ class SequenceDispatcher : public NetQueryCallback {
   void close_silent();
 
  private:
-  enum class State { Start, Wait, Finish, Dummy };
+  enum class State : int32 { Start, Wait, Finish, Dummy };
   struct Data {
     State state_;
     NetQueryRef net_query_ref_;
diff --git a/td/telegram/StateManager.cpp b/td/telegram/StateManager.cpp
index 6777f441..11171d54 100644
--- a/td/telegram/StateManager.cpp
+++ b/td/telegram/StateManager.cpp
@@ -58,12 +58,12 @@ void StateManager::do_on_network(NetType new_network_type, bool inc_generation)
   if (inc_generation) {
     network_generation_++;
   }
-  notify_flags(NetworkFlag);
+  notify_flag(Flag::Network);
 }
 
 void StateManager::on_online(bool is_online) {
   online_flag_ = is_online;
-  notify_flags(OnlineFlag);
+  notify_flag(Flag::Online);
 }
 
 void StateManager::on_proxy(bool use_proxy) {
@@ -105,18 +105,21 @@ StateManager::State StateManager::get_real_state() const {
   return State::Ready;
 }
 
-void StateManager::notify_flags(int32 flags) {
+void StateManager::notify_flag(Flag flag) {
   for (auto it = callbacks_.begin(); it != callbacks_.end();) {
-    bool ok = true;
-    if (flags & OnlineFlag) {
-      ok &= (*it)->on_online(online_flag_);
-    }
-    if (flags & StateFlag) {
-      ok &= (*it)->on_state(flush_state_);
-    }
-    if (flags & NetworkFlag) {
-      ok &= (*it)->on_network(network_type_, network_generation_);
-    }
+    bool ok = [&] {
+      switch (flag) {
+        case Flag::Online:
+          return (*it)->on_online(online_flag_);
+        case Flag::State:
+          return (*it)->on_state(flush_state_);
+        case Flag::Network:
+          return (*it)->on_network(network_type_, network_generation_);
+        default:
+          UNREACHABLE();
+          return true;
+      }
+    }();
     if (ok) {
       ++it;
     } else {
@@ -165,7 +168,7 @@ void StateManager::loop() {
     if (now >= pending_timestamp_ + delay) {
       has_timestamp_ = false;
       flush_state_ = pending_state_;
-      notify_flags(StateFlag);
+      notify_flag(Flag::State);
     } else {
       set_timeout_at(pending_timestamp_ + delay);
     }
diff --git a/td/telegram/StateManager.h b/td/telegram/StateManager.h
index cbe24c22..9582db7c 100644
--- a/td/telegram/StateManager.h
+++ b/td/telegram/StateManager.h
@@ -114,8 +114,8 @@ class StateManager final : public Actor {
   void inc_connect();
   void dec_connect();
 
-  enum Flags { OnlineFlag = 1, StateFlag = 2, NetworkFlag = 4 };
-  void notify_flags(int32 flags);
+  enum class Flag : int32 { Online, State, Network };
+  void notify_flag(Flag flag);
 
   void start_up() override;
   void loop() override;
diff --git a/td/telegram/Td.h b/td/telegram/Td.h
index 74051602..fa62d584 100644
--- a/td/telegram/Td.h
+++ b/td/telegram/Td.h
@@ -230,7 +230,7 @@ class Td final : public NetQueryCallback {
   bool destroy_flag_ = false;
   int close_flag_ = 0;
 
-  enum class State { WaitParameters, Decrypt, Run, Close } state_ = State::WaitParameters;
+  enum class State : int32 { WaitParameters, Decrypt, Run, Close } state_ = State::WaitParameters;
   EncryptionInfo encryption_info_;
 
   vector<std::pair<uint64, std::shared_ptr<ResultHandler>>> result_handlers_;
diff --git a/td/telegram/TopDialogManager.h b/td/telegram/TopDialogManager.h
index c301e425..77407cd7 100644
--- a/td/telegram/TopDialogManager.h
+++ b/td/telegram/TopDialogManager.h
@@ -23,7 +23,7 @@
 #include <utility>
 
 namespace td {
-enum class TopDialogCategory { Correspondent, BotPM, BotInline, Group, Channel, Call, Size };
+enum class TopDialogCategory : int32 { Correspondent, BotPM, BotInline, Group, Channel, Call, Size };
 
 inline TopDialogCategory top_dialog_category_from_td_api(const td_api::TopChatCategory &category) {
   switch (category.get_id()) {
@@ -65,7 +65,7 @@ class TopDialogManager : public NetQueryCallback {
 
   bool is_active_{false};
   bool was_first_sync_{false};
-  enum class SyncState { None, Pending, Ok };
+  enum class SyncState : int32 { None, Pending, Ok };
   SyncState db_sync_state_ = SyncState::None;
   Timestamp first_unsync_change_;
   SyncState server_sync_state_ = SyncState::None;
diff --git a/td/telegram/UpdatesManager.h b/td/telegram/UpdatesManager.h
index 9602fee7..b19f3d00 100644
--- a/td/telegram/UpdatesManager.h
+++ b/td/telegram/UpdatesManager.h
@@ -112,7 +112,7 @@ class UpdatesManager : public Actor {
 
   class State {
    public:
-    enum class Type {
+    enum class Type : int32 {
       General,
       RunningGetUpdatesState,
       RunningGetDifference,
diff --git a/td/telegram/files/FileHashUploader.cpp b/td/telegram/files/FileHashUploader.cpp
index 2408e16d..6af72c91 100644
--- a/td/telegram/files/FileHashUploader.cpp
+++ b/td/telegram/files/FileHashUploader.cpp
@@ -56,10 +56,10 @@ void FileHashUploader::loop() {
 }
 
 Status FileHashUploader::loop_impl() {
-  if (state_ == CalcSha) {
+  if (state_ == State::CalcSha) {
     TRY_STATUS(loop_sha());
   }
-  if (state_ == NetRequest) {
+  if (state_ == State::NetRequest) {
     // messages.getDocumentByHash#338e2464 sha256:bytes size:int mime_type:string = Document;
     auto hash = BufferSlice(32);
     sha256_final(&sha256_state_, hash.as_slice());
@@ -69,7 +69,7 @@ Status FileHashUploader::loop_impl() {
     LOG(INFO) << "Send getDocumentByHash request: " << to_string(query);
     auto ptr = G()->net_query_creator().create(create_storer(query));
     G()->net_query_dispatcher().dispatch_with_callback(std::move(ptr), actor_shared(this));
-    state_ = WaitNetResult;
+    state_ = State::WaitNetResult;
   }
   return Status::OK();
 }
@@ -102,7 +102,7 @@ Status FileHashUploader::loop_sha() {
   size_left_ -= narrow_cast<int64>(read_size);
   CHECK(size_left_ >= 0);
   if (size_left_ == 0) {
-    state_ = NetRequest;
+    state_ = State::NetRequest;
     return Status::OK();
   }
   return Status::OK();
diff --git a/td/telegram/files/FileHashUploader.h b/td/telegram/files/FileHashUploader.h
index d836c521..f47d5340 100644
--- a/td/telegram/files/FileHashUploader.h
+++ b/td/telegram/files/FileHashUploader.h
@@ -60,7 +60,7 @@ class FileHashUploader : public FileLoaderActor {
 
   ActorShared<ResourceManager> resource_manager_;
 
-  enum { CalcSha, NetRequest, WaitNetResult } state_ = CalcSha;
+  enum class State : int32 { CalcSha, NetRequest, WaitNetResult } state_ = State::CalcSha;
   bool stop_flag_ = false;
   Sha256State sha256_state_;
 
diff --git a/td/telegram/files/FileLoader.cpp b/td/telegram/files/FileLoader.cpp
index a7d02824..f6d855ed 100644
--- a/td/telegram/files/FileLoader.cpp
+++ b/td/telegram/files/FileLoader.cpp
@@ -123,7 +123,7 @@ Status FileLoader::do_loop() {
   }
   for (auto &query : check_info.queries) {
     G()->net_query_dispatcher().dispatch_with_callback(
-        std::move(query), actor_shared(this, UniqueId::next(UniqueId::Type::Default, CommonQueryKey)));
+        std::move(query), actor_shared(this, UniqueId::next(UniqueId::Type::Default, COMMON_QUERY_KEY)));
   }
   if (check_info.need_check) {
     parts_manager_.set_need_check();
@@ -209,7 +209,7 @@ void FileLoader::on_result(NetQueryPtr query) {
   if (id == blocking_id_) {
     blocking_id_ = 0;
   }
-  if (UniqueId::extract_key(id) == CommonQueryKey) {
+  if (UniqueId::extract_key(id) == COMMON_QUERY_KEY) {
     on_common_query(std::move(query));
     return loop();
   }
diff --git a/td/telegram/files/FileLoader.h b/td/telegram/files/FileLoader.h
index a97a5199..8ee3160d 100644
--- a/td/telegram/files/FileLoader.h
+++ b/td/telegram/files/FileLoader.h
@@ -95,7 +95,7 @@ class FileLoader : public FileLoaderActor {
   }
 
  private:
-  enum { CommonQueryKey = 2 };
+  static constexpr uint8 COMMON_QUERY_KEY = 2;
   bool stop_flag_ = false;
   ActorShared<ResourceManager> resource_manager_;
   ResourceState resource_state_;
diff --git a/td/telegram/files/FileLocation.h b/td/telegram/files/FileLocation.h
index bd78637b..c4fd4ddc 100644
--- a/td/telegram/files/FileLocation.h
+++ b/td/telegram/files/FileLocation.h
@@ -157,7 +157,7 @@ constexpr int32 file_type_size = static_cast<int32>(FileType::Size);
 extern const char *file_type_name[file_type_size];
 
 struct FileEncryptionKey {
-  enum class Type { None, Secret, Secure };
+  enum class Type : int32 { None, Secret, Secure };
   FileEncryptionKey() = default;
   FileEncryptionKey(Slice key, Slice iv) : key_iv_(key.size() + iv.size(), '\0'), type_(Type::Secret) {
     if (key.size() != 32 || iv.size() != 32) {
@@ -459,7 +459,7 @@ class FullRemoteFileLocation {
   static constexpr int32 WEB_LOCATION_FLAG = 1 << 24;
   bool web_location_flag_{false};
   DcId dc_id_;
-  enum class LocationType { Web, Photo, Common, None };
+  enum class LocationType : int32 { Web, Photo, Common, None };
   Variant<WebRemoteFileLocation, PhotoRemoteFileLocation, CommonRemoteFileLocation> variant_;
 
   LocationType location_type() const {
diff --git a/td/telegram/files/FileManager.h b/td/telegram/files/FileManager.h
index bfa4ab91..1f2bc076 100644
--- a/td/telegram/files/FileManager.h
+++ b/td/telegram/files/FileManager.h
@@ -368,7 +368,7 @@ class FileManager : public FileLoadManager::Callback {
   class Query {
    public:
     FileId file_id_;
-    enum Type { UploadByHash, Upload, Download, SetContent, Generate } type_;
+    enum Type : int32 { UploadByHash, Upload, Download, SetContent, Generate } type_;
   };
   struct FileIdInfo {
     FileNodeId node_id_{0};
diff --git a/td/telegram/files/PartsManager.h b/td/telegram/files/PartsManager.h
index 26c31d51..a2f07381 100644
--- a/td/telegram/files/PartsManager.h
+++ b/td/telegram/files/PartsManager.h
@@ -49,7 +49,7 @@ class PartsManager {
   static constexpr int MAX_PART_SIZE = 512 * (1 << 10);
   static constexpr int64 MAX_FILE_SIZE = MAX_PART_SIZE * MAX_PART_COUNT;
 
-  enum class PartStatus { Empty, Pending, Ready };
+  enum class PartStatus : int32 { Empty, Pending, Ready };
 
   bool need_check_{false};
   int64 checked_prefix_size_{0};
diff --git a/td/telegram/files/ResourceManager.h b/td/telegram/files/ResourceManager.h
index 48a32f18..e12f65b6 100644
--- a/td/telegram/files/ResourceManager.h
+++ b/td/telegram/files/ResourceManager.h
@@ -20,7 +20,7 @@
 namespace td {
 class ResourceManager : public Actor {
  public:
-  enum class Mode { Baseline, Greedy };
+  enum class Mode : int32 { Baseline, Greedy };
   explicit ResourceManager(Mode mode) : mode_(mode) {
   }
   // use through ActorShared
diff --git a/td/telegram/net/ConnectionCreator.h b/td/telegram/net/ConnectionCreator.h
index 1c5dbc8d..7265cdab 100644
--- a/td/telegram/net/ConnectionCreator.h
+++ b/td/telegram/net/ConnectionCreator.h
@@ -98,7 +98,7 @@ class Proxy {
     return password_;
   }
 
-  enum class Type { None, Socks5 };
+  enum class Type : int32 { None, Socks5 };
   Type type() const {
     return type_;
   }
diff --git a/td/telegram/net/DcAuthManager.h b/td/telegram/net/DcAuthManager.h
index a8710f61..4806a8c8 100644
--- a/td/telegram/net/DcAuthManager.h
+++ b/td/telegram/net/DcAuthManager.h
@@ -31,7 +31,7 @@ class DcAuthManager : public NetQueryCallback {
     std::shared_ptr<AuthDataShared> shared_auth_data;
     AuthState auth_state;
 
-    enum class State { Waiting, Export, Import, BeforeOk, Ok };
+    enum class State : int32 { Waiting, Export, Import, BeforeOk, Ok };
     State state = State::Waiting;
     uint64 wait_id;
     int32 export_id;
diff --git a/td/telegram/net/DcId.h b/td/telegram/net/DcId.h
index f258d340..092d9087 100644
--- a/td/telegram/net/DcId.h
+++ b/td/telegram/net/DcId.h
@@ -71,7 +71,7 @@ class DcId {
   }
 
  private:
-  enum { Empty = 0, MainDc = -1, Invalid = -2 };
+  enum : int32 { Empty = 0, MainDc = -1, Invalid = -2 };
   int32 dc_id_{Empty};
   bool is_external_{false};
 
diff --git a/td/telegram/net/DcOptions.h b/td/telegram/net/DcOptions.h
index 9ce5aeb4..191f0098 100644
--- a/td/telegram/net/DcOptions.h
+++ b/td/telegram/net/DcOptions.h
@@ -21,7 +21,7 @@
 namespace td {
 class DcOption {
   // do not forget to update PrintFlags
-  enum Flags { IPv6 = 1, MediaOnly = 2, ObfuscatedTcpOnly = 4, Cdn = 8, Static = 16 };
+  enum Flags : int32 { IPv6 = 1, MediaOnly = 2, ObfuscatedTcpOnly = 4, Cdn = 8, Static = 16 };
 
   int32 flags = 0;
   DcId dc_id;
diff --git a/td/telegram/net/DcOptionsSet.h b/td/telegram/net/DcOptionsSet.h
index e57e9003..386cfad4 100644
--- a/td/telegram/net/DcOptionsSet.h
+++ b/td/telegram/net/DcOptionsSet.h
@@ -26,7 +26,7 @@ class DcOptionsSet {
     double ok_at{-1000};
     double error_at{-1001};
     double check_at{-1002};
-    enum State { Ok, Error, Checking };
+    enum State : int32 { Ok, Error, Checking };
 
     void on_ok() {
       ok_at = Time::now_cached();
@@ -63,7 +63,7 @@ class DcOptionsSet {
   void reset();
 
  private:
-  enum class State { Error, Ok, Checking };
+  enum class State : int32 { Error, Ok, Checking };
 
   struct OptionStat {
     Stat tcp_stat;
diff --git a/td/telegram/net/NetQuery.h b/td/telegram/net/NetQuery.h
index da1bdaed..003ac516 100644
--- a/td/telegram/net/NetQuery.h
+++ b/td/telegram/net/NetQuery.h
@@ -47,7 +47,7 @@ class NetQuery : public ListNode {
   NetQuery() = default;
 
   enum class State : int8 { Empty, Query, OK, Error };
-  enum class Type { Common, Upload, Download, DownloadSmall };
+  enum class Type : int8 { Common, Upload, Download, DownloadSmall };
   enum class AuthFlag : int8 { Off, On };
   enum class GzipFlag : int8 { Off, On };
   enum Error : int32 { Resend = 202, Cancelled = 203, ResendInvokeAfter = 204 };
diff --git a/td/telegram/net/Session.h b/td/telegram/net/Session.h
index 93f69a27..f2792bf3 100644
--- a/td/telegram/net/Session.h
+++ b/td/telegram/net/Session.h
@@ -94,7 +94,7 @@ class Session final
   // Just re-ask answer_id each time we get information about it.
   // Thought mtproto::Connection must ensure delivery of such query
 
-  enum class Mode { Tcp, Http } mode_ = Mode::Tcp;
+  enum class Mode : int8 { Tcp, Http } mode_ = Mode::Tcp;
   bool is_main_;
   bool is_cdn_;
   bool was_on_network_ = false;
@@ -120,7 +120,7 @@ class Session final
   struct ConnectionInfo {
     int8 connection_id;
     Mode mode;
-    enum class State { Empty, Connecting, Ready } state = State::Empty;
+    enum class State : int8 { Empty, Connecting, Ready } state = State::Empty;
     mtproto::AuthKeyHandshake handshake;
     mtproto::AuthKeyHandshake tmp_handshake;
     unique_ptr<mtproto::SessionConnection> connection;