diff --git a/td/generate/scheme/td_api.tl b/td/generate/scheme/td_api.tl
index ada1f35a..cc738075 100644
--- a/td/generate/scheme/td_api.tl
+++ b/td/generate/scheme/td_api.tl
@@ -1837,9 +1837,10 @@ languagePackStrings strings:vector<languagePackString> = LanguagePackStrings;
 //@name Language name @native_name Name of the language in that language
 //@plural_code A language code to be used to apply plural forms. See https://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html for more info
 //@is_official True, if the language pack is official @is_rtl True, if the language pack strings are RTL @is_beta True, if the language pack is a beta language pack
+//@is_installed True, if the language pack is installed by the current user
 //@total_string_count Total number of non-deleted strings from the language pack @translated_string_count Total number of translated strings from the language pack
 //@local_string_count Total number of non-deleted strings from the language pack available locally @translation_url Link to language translation interface; empty for custom local language packs
-languagePackInfo id:string base_language_pack_id:string name:string native_name:string plural_code:string is_official:Bool is_rtl:Bool is_beta:Bool total_string_count:int32 translated_string_count:int32 local_string_count:int32 translation_url:string = LanguagePackInfo;
+languagePackInfo id:string base_language_pack_id:string name:string native_name:string plural_code:string is_official:Bool is_rtl:Bool is_beta:Bool is_installed:Bool total_string_count:int32 translated_string_count:int32 local_string_count:int32 translation_url:string = LanguagePackInfo;
 
 //@description Contains information about the current localization target @language_packs List of available language packs for this application
 localizationTargetInfo language_packs:vector<languagePackInfo> = LocalizationTargetInfo;
@@ -3410,7 +3411,7 @@ getLanguagePackInfo language_pack_id:string = LanguagePackInfo;
 //@description Returns strings from a language pack in the current localization target by their keys @language_pack_id Language pack identifier of the strings to be returned @keys Language pack keys of the strings to be returned; leave empty to request all available strings
 getLanguagePackStrings language_pack_id:string keys:vector<string> = LanguagePackStrings;
 
-//@description Adds a custom server language pack to the current localization target @language_pack_id Identifier of a language pack to be added; may be different from a name that is used in an "https://t.me/setlanguage/" link
+//@description Adds a custom server language pack to the list of installed language packs in current localization target @language_pack_id Identifier of a language pack to be added; may be different from a name that is used in an "https://t.me/setlanguage/" link
 addCustomServerLanguagePack language_pack_id:string = Ok;
 
 //@description Adds or changes a custom local language pack to the current localization target @info Information about the language pack. Language pack ID must start with 'X', consist only of English letters, digits and hyphens, and must not exceed 64 characters @strings Strings of the new language pack
diff --git a/td/generate/scheme/td_api.tlo b/td/generate/scheme/td_api.tlo
index 5f3733f4..be5a80c3 100644
Binary files a/td/generate/scheme/td_api.tlo and b/td/generate/scheme/td_api.tlo differ
diff --git a/td/telegram/LanguagePackManager.cpp b/td/telegram/LanguagePackManager.cpp
index 2a66caa3..6943242c 100644
--- a/td/telegram/LanguagePackManager.cpp
+++ b/td/telegram/LanguagePackManager.cpp
@@ -767,9 +767,10 @@ void LanguagePackManager::search_language_info(string language_code,
 
 td_api::object_ptr<td_api::languagePackInfo> LanguagePackManager::get_language_pack_info_object(
     const string &language_code, const LanguageInfo &info) {
-  return td_api::make_object<td_api::languagePackInfo>(
-      language_code, info.base_language_code_, info.name_, info.native_name_, info.plural_code_, info.is_official_,
-      info.is_rtl_, info.is_beta_, info.total_string_count_, info.translated_string_count_, 0, info.translation_url_);
+  return td_api::make_object<td_api::languagePackInfo>(language_code, info.base_language_code_, info.name_,
+                                                       info.native_name_, info.plural_code_, info.is_official_,
+                                                       info.is_rtl_, info.is_beta_, false, info.total_string_count_,
+                                                       info.translated_string_count_, 0, info.translation_url_);
 }
 
 string LanguagePackManager::get_language_info_string(const LanguageInfo &info) {
@@ -835,9 +836,11 @@ void LanguagePackManager::on_get_languages(vector<tl_object_ptr<telegram_api::la
   auto results = td_api::make_object<td_api::localizationTargetInfo>();
   std::unordered_set<string> added_languages;
 
-  auto add_language_info = [&results, &added_languages](const string &language_code, const LanguageInfo &info) {
+  auto add_language_info = [&results, &added_languages](const string &language_code, const LanguageInfo &info,
+                                                        bool is_installed) {
     if (added_languages.insert(language_code).second) {
       results->language_packs_.push_back(get_language_pack_info_object(language_code, info));
+      results->language_packs_.back()->is_installed_ = is_installed;
     }
   };
 
@@ -848,11 +851,11 @@ void LanguagePackManager::on_get_languages(vector<tl_object_ptr<telegram_api::la
       LanguagePack *pack = pack_it->second.get();
       std::lock_guard<std::mutex> pack_lock(pack->mutex_);
       for (auto &info : pack->custom_language_pack_infos_) {
-        add_language_info(info.first, info.second);
+        add_language_info(info.first, info.second, true);
       }
       if (only_local) {
         for (auto &info : pack->server_language_pack_infos_) {
-          add_language_info(info.first, info.second);
+          add_language_info(info.first, info.second, false);
         }
       }
     }
@@ -865,7 +868,7 @@ void LanguagePackManager::on_get_languages(vector<tl_object_ptr<telegram_api::la
       continue;
     }
 
-    add_language_info(language->lang_code_, r_info.ok());
+    add_language_info(language->lang_code_, r_info.ok(), false);
     all_server_infos.emplace_back(std::move(language->lang_code_), r_info.move_as_ok());
   }
 
@@ -911,6 +914,10 @@ void LanguagePackManager::on_get_language(tl_object_ptr<telegram_api::langPackLa
   if (pack_it != database_->language_packs_.end()) {
     LanguagePack *pack = pack_it->second.get();
     std::lock_guard<std::mutex> pack_lock(pack->mutex_);
+
+    result->is_installed_ = pack->custom_language_pack_infos_.count(lang_pack_language->lang_code_) != 0 ||
+                            pack->custom_language_pack_infos_.count(language_code) != 0;
+
     bool is_changed = false;
     for (auto &info : pack->server_language_pack_infos_) {
       if (info.first == lang_pack_language->lang_code_ || info.first == language_code) {
@@ -926,6 +933,8 @@ void LanguagePackManager::on_get_language(tl_object_ptr<telegram_api::langPackLa
     if (is_changed) {
       save_server_language_pack_infos(pack);
     }
+  } else {
+    LOG(ERROR) << "Failed to find localization target " << language_pack;
   }
 
   promise.set_value(std::move(result));
diff --git a/td/telegram/cli.cpp b/td/telegram/cli.cpp
index 22654ddf..7da64674 100644
--- a/td/telegram/cli.cpp
+++ b/td/telegram/cli.cpp
@@ -1193,7 +1193,7 @@ class CliClient final : public Actor {
                                                                             const string &name,
                                                                             const string &native_name) {
     return td_api::make_object<td_api::languagePackInfo>(language_code, "test", name, native_name, "en", true, true,
-                                                         true, -1, 5, 3, "abacaba");
+                                                         true, true, -1, 5, 3, "abacaba");
   }
 
   static td_api::object_ptr<td_api::Object> execute(tl_object_ptr<td_api::Function> f) {
diff --git a/td/telegram/files/FileUploader.cpp b/td/telegram/files/FileUploader.cpp
index ec675720..152323e1 100644
--- a/td/telegram/files/FileUploader.cpp
+++ b/td/telegram/files/FileUploader.cpp
@@ -102,7 +102,7 @@ Result<FileLoader::PrefixInfo> FileUploader::on_update_local_location(const Loca
   }
 
   string path;
-  int64 local_size = 0;
+  int64 local_size = -1;
   bool local_is_ready{false};
   FileType file_type{FileType::Temp};
   if (location.type() == LocalFileLocation::Type::Empty ||