diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6097dbe13..affd6ca02 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -427,6 +427,7 @@ set(TDLIB_SOURCE
   td/telegram/net/SessionMultiProxy.cpp
   td/telegram/NewPasswordState.cpp
   td/telegram/NotificationGroupInfo.cpp
+  td/telegram/NotificationGroupType.cpp
   td/telegram/NotificationManager.cpp
   td/telegram/NotificationSettingsScope.cpp
   td/telegram/NotificationSettingsManager.cpp
diff --git a/td/telegram/NotificationGroupType.cpp b/td/telegram/NotificationGroupType.cpp
new file mode 100644
index 000000000..efc5eecaa
--- /dev/null
+++ b/td/telegram/NotificationGroupType.cpp
@@ -0,0 +1,88 @@
+//
+// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+#include "td/telegram/NotificationGroupType.h"
+
+namespace td {
+
+bool is_database_notification_group_type(NotificationGroupType type) {
+  switch (type) {
+    case NotificationGroupType::Messages:
+    case NotificationGroupType::Mentions:
+    case NotificationGroupType::SecretChat:
+      return true;
+    case NotificationGroupType::Calls:
+      return false;
+    default:
+      UNREACHABLE();
+      return false;
+  }
+}
+
+bool is_partial_notification_group_type(NotificationGroupType type) {
+  switch (type) {
+    case NotificationGroupType::Messages:
+    case NotificationGroupType::Mentions:
+      return true;
+    case NotificationGroupType::SecretChat:
+    case NotificationGroupType::Calls:
+      return false;
+    default:
+      UNREACHABLE();
+      return false;
+  }
+}
+
+td_api::object_ptr<td_api::NotificationGroupType> get_notification_group_type_object(NotificationGroupType type) {
+  switch (type) {
+    case NotificationGroupType::Messages:
+      return td_api::make_object<td_api::notificationGroupTypeMessages>();
+    case NotificationGroupType::Mentions:
+      return td_api::make_object<td_api::notificationGroupTypeMentions>();
+    case NotificationGroupType::SecretChat:
+      return td_api::make_object<td_api::notificationGroupTypeSecretChat>();
+    case NotificationGroupType::Calls:
+      return td_api::make_object<td_api::notificationGroupTypeCalls>();
+    default:
+      UNREACHABLE();
+      return nullptr;
+  }
+}
+
+NotificationGroupType get_notification_group_type(const td_api::object_ptr<td_api::NotificationGroupType> &type) {
+  CHECK(type != nullptr);
+  switch (type->get_id()) {
+    case td_api::notificationGroupTypeMessages::ID:
+      return NotificationGroupType::Messages;
+    case td_api::notificationGroupTypeMentions::ID:
+      return NotificationGroupType::Mentions;
+    case td_api::notificationGroupTypeSecretChat::ID:
+      return NotificationGroupType::SecretChat;
+    case td_api::notificationGroupTypeCalls::ID:
+      return NotificationGroupType::Calls;
+    default:
+      UNREACHABLE();
+      return NotificationGroupType::Calls;
+  }
+}
+
+StringBuilder &operator<<(StringBuilder &string_builder, const NotificationGroupType &type) {
+  switch (type) {
+    case NotificationGroupType::Messages:
+      return string_builder << "Messages";
+    case NotificationGroupType::Mentions:
+      return string_builder << "Mentions";
+    case NotificationGroupType::SecretChat:
+      return string_builder << "SecretChat";
+    case NotificationGroupType::Calls:
+      return string_builder << "Calls";
+    default:
+      UNREACHABLE();
+      return string_builder;
+  }
+}
+
+}  // namespace td
diff --git a/td/telegram/NotificationGroupType.h b/td/telegram/NotificationGroupType.h
index fe4dc3231..7b6a81376 100644
--- a/td/telegram/NotificationGroupType.h
+++ b/td/telegram/NotificationGroupType.h
@@ -15,83 +15,14 @@ namespace td {
 
 enum class NotificationGroupType : int8 { Messages, Mentions, SecretChat, Calls };
 
-inline bool is_database_notification_group_type(NotificationGroupType type) {
-  switch (type) {
-    case NotificationGroupType::Messages:
-    case NotificationGroupType::Mentions:
-    case NotificationGroupType::SecretChat:
-      return true;
-    case NotificationGroupType::Calls:
-      return false;
-    default:
-      UNREACHABLE();
-      return false;
-  }
-}
+bool is_database_notification_group_type(NotificationGroupType type);
 
-inline bool is_partial_notification_group_type(NotificationGroupType type) {
-  switch (type) {
-    case NotificationGroupType::Messages:
-    case NotificationGroupType::Mentions:
-      return true;
-    case NotificationGroupType::SecretChat:
-    case NotificationGroupType::Calls:
-      return false;
-    default:
-      UNREACHABLE();
-      return false;
-  }
-}
+bool is_partial_notification_group_type(NotificationGroupType type);
 
-inline td_api::object_ptr<td_api::NotificationGroupType> get_notification_group_type_object(
-    NotificationGroupType type) {
-  switch (type) {
-    case NotificationGroupType::Messages:
-      return td_api::make_object<td_api::notificationGroupTypeMessages>();
-    case NotificationGroupType::Mentions:
-      return td_api::make_object<td_api::notificationGroupTypeMentions>();
-    case NotificationGroupType::SecretChat:
-      return td_api::make_object<td_api::notificationGroupTypeSecretChat>();
-    case NotificationGroupType::Calls:
-      return td_api::make_object<td_api::notificationGroupTypeCalls>();
-    default:
-      UNREACHABLE();
-      return nullptr;
-  }
-}
+td_api::object_ptr<td_api::NotificationGroupType> get_notification_group_type_object(NotificationGroupType type);
 
-inline NotificationGroupType get_notification_group_type(
-    const td_api::object_ptr<td_api::NotificationGroupType> &type) {
-  CHECK(type != nullptr);
-  switch (type->get_id()) {
-    case td_api::notificationGroupTypeMessages::ID:
-      return NotificationGroupType::Messages;
-    case td_api::notificationGroupTypeMentions::ID:
-      return NotificationGroupType::Mentions;
-    case td_api::notificationGroupTypeSecretChat::ID:
-      return NotificationGroupType::SecretChat;
-    case td_api::notificationGroupTypeCalls::ID:
-      return NotificationGroupType::Calls;
-    default:
-      UNREACHABLE();
-      return NotificationGroupType::Calls;
-  }
-}
+NotificationGroupType get_notification_group_type(const td_api::object_ptr<td_api::NotificationGroupType> &type);
 
-inline StringBuilder &operator<<(StringBuilder &sb, const NotificationGroupType &type) {
-  switch (type) {
-    case NotificationGroupType::Messages:
-      return sb << "Messages";
-    case NotificationGroupType::Mentions:
-      return sb << "Mentions";
-    case NotificationGroupType::SecretChat:
-      return sb << "SecretChat";
-    case NotificationGroupType::Calls:
-      return sb << "Calls";
-    default:
-      UNREACHABLE();
-      return sb;
-  }
-}
+StringBuilder &operator<<(StringBuilder &string_builder, const NotificationGroupType &type);
 
 }  // namespace td