diff --git a/editor/osm_editor.cpp b/editor/osm_editor.cpp
index 23dfd66b71..430d8056c0 100644
--- a/editor/osm_editor.cpp
+++ b/editor/osm_editor.cpp
@@ -302,6 +302,11 @@ void Editor::ClearAllLocalEdits()
   Invalidate();
 }
 
+void Editor::OnMapRegistered(platform::LocalCountryFile const & localFile)
+{
+  LoadEdits();
+}
+
 void Editor::OnMapDeregistered(platform::LocalCountryFile const & localFile)
 {
   // Can be called on non-main-thread in case of simultaneous uploading process.
diff --git a/editor/osm_editor.hpp b/editor/osm_editor.hpp
index e0264e323d..d3f45d581d 100644
--- a/editor/osm_editor.hpp
+++ b/editor/osm_editor.hpp
@@ -122,12 +122,8 @@ public:
   /// Resets editor to initial state: no any edits or created/deleted features.
   void ClearAllLocalEdits();
 
-  void OnMapUpdated(platform::LocalCountryFile const &,
-                    platform::LocalCountryFile const &) override
-  {
-    LoadEdits();
-  }
-
+  // MwmSet::Observer overrides:
+  void OnMapRegistered(platform::LocalCountryFile const & localFile) override;
   void OnMapDeregistered(platform::LocalCountryFile const & localFile) override;
 
   using FeatureIndexFunctor = std::function<void(uint32_t)>;
diff --git a/indexer/indexer_tests/data_source_test.cpp b/indexer/indexer_tests/data_source_test.cpp
index 2b80c2a71f..3d9beb9839 100644
--- a/indexer/indexer_tests/data_source_test.cpp
+++ b/indexer/indexer_tests/data_source_test.cpp
@@ -38,12 +38,6 @@ public:
     AddEvent(m_expected, MwmSet::Event::TYPE_REGISTERED, localFile);
   }
 
-  void ExpectUpdated(platform::LocalCountryFile const & newFile,
-                     platform::LocalCountryFile const & oldFile)
-  {
-    AddEvent(m_expected, MwmSet::Event::TYPE_UPDATED, newFile, oldFile);
-  }
-
   void ExpectDeregistered(platform::LocalCountryFile const & localFile)
   {
     AddEvent(m_expected, MwmSet::Event::TYPE_DEREGISTERED, localFile);
@@ -69,12 +63,6 @@ public:
     AddEvent(m_actual, MwmSet::Event::TYPE_REGISTERED, localFile);
   }
 
-  void OnMapUpdated(platform::LocalCountryFile const & newFile,
-                    platform::LocalCountryFile const & oldFile) override
-  {
-    AddEvent(m_actual, MwmSet::Event::TYPE_UPDATED, newFile, oldFile);
-  }
-
   void OnMapDeregistered(platform::LocalCountryFile const & localFile) override
   {
     AddEvent(m_actual, MwmSet::Event::TYPE_DEREGISTERED, localFile);
@@ -107,7 +95,7 @@ UNIT_CLASS_TEST(DataSourceTest, StatusNotifications)
   CountryFile const country("minsk-pass");
 
   // These two classes point to the same file, but will be considered
-  // by Index as distinct files because versions are artificially set
+  // by DataSource as distinct files because versions are artificially set
   // to different numbers.
   LocalCountryFile const file1(mapsDir, country, 1 /* version */);
   LocalCountryFile const file2(mapsDir, country, 2 /* version */);
@@ -147,7 +135,8 @@ UNIT_CLASS_TEST(DataSourceTest, StatusNotifications)
     TEST(id2.IsAlive(), ());
     TEST_NOT_EQUAL(id1, id2, ());
 
-    ExpectUpdated(file2, file1);
+    ExpectDeregistered(file1);
+    ExpectRegistered(file2);
     TEST(CheckExpectations(), ());
   }
 
diff --git a/indexer/mwm_set.cpp b/indexer/mwm_set.cpp
index 8496c0c5b3..fb414515bc 100644
--- a/indexer/mwm_set.cpp
+++ b/indexer/mwm_set.cpp
@@ -112,17 +112,8 @@ pair<MwmSet::MwmId, MwmSet::RegResult> MwmSet::Register(LocalCountryFile const &
     // Deregister old mwm for the country.
     if (info->GetVersion() < localFile.GetVersion())
     {
-      EventList subEvents;
-      DeregisterImpl(id, subEvents);
-      result = RegisterImpl(localFile, subEvents);
-
-      // In the case of success all sub-events are
-      // replaced with a single UPDATE event. Otherwise,
-      // sub-events are reported as is.
-      if (result.second == MwmSet::RegResult::Success)
-        events.Add(Event(Event::TYPE_UPDATED, localFile, info->GetLocalFile()));
-      else
-        events.Append(subEvents);
+      DeregisterImpl(id, events);
+      result = RegisterImpl(localFile, events);
       return;
     }
 
@@ -239,7 +230,8 @@ void MwmSet::SetStatus(MwmInfo & info, MwmInfo::Status status, EventList & event
   case MwmInfo::STATUS_REGISTERED:
     events.Add(Event(Event::TYPE_REGISTERED, info.GetLocalFile()));
     break;
-  case MwmInfo::STATUS_MARKED_TO_DEREGISTER: break;
+  case MwmInfo::STATUS_MARKED_TO_DEREGISTER:
+    break;
   case MwmInfo::STATUS_DEREGISTERED:
     events.Add(Event(Event::TYPE_DEREGISTERED, info.GetLocalFile()));
     break;
@@ -255,9 +247,6 @@ void MwmSet::ProcessEventList(EventList & events)
     case Event::TYPE_REGISTERED:
       m_observers.ForEach(&Observer::OnMapRegistered, event.m_file);
       break;
-    case Event::TYPE_UPDATED:
-      m_observers.ForEach(&Observer::OnMapUpdated, event.m_file, event.m_oldFile);
-      break;
     case Event::TYPE_DEREGISTERED:
       m_observers.ForEach(&Observer::OnMapDeregistered, event.m_file);
       break;
@@ -456,7 +445,6 @@ string DebugPrint(MwmSet::Event::Type type)
   switch (type)
   {
     case MwmSet::Event::TYPE_REGISTERED: return "Registered";
-    case MwmSet::Event::TYPE_UPDATED: return "Updated";
     case MwmSet::Event::TYPE_DEREGISTERED: return "Deregistered";
   }
   return "Undefined";
@@ -465,9 +453,6 @@ string DebugPrint(MwmSet::Event::Type type)
 string DebugPrint(MwmSet::Event const & event)
 {
   ostringstream os;
-  os << "MwmSet::Event [" << DebugPrint(event.m_type) << ", " << DebugPrint(event.m_file);
-  if (event.m_type == MwmSet::Event::TYPE_UPDATED)
-    os << ", " << DebugPrint(event.m_oldFile);
-  os << "]";
+  os << "MwmSet::Event [" << DebugPrint(event.m_type) << ", " << DebugPrint(event.m_file) << "]";
   return os.str();
 }
diff --git a/indexer/mwm_set.hpp b/indexer/mwm_set.hpp
index 406eebac87..4e102e788e 100644
--- a/indexer/mwm_set.hpp
+++ b/indexer/mwm_set.hpp
@@ -184,7 +184,6 @@ public:
     {
       TYPE_REGISTERED,
       TYPE_DEREGISTERED,
-      TYPE_UPDATED,
     };
 
     Event() = default;
@@ -248,18 +247,11 @@ public:
   public:
     virtual ~Observer() = default;
 
-    // Called when a map is registered for a first time and can be
-    // used.
-    virtual void OnMapRegistered(platform::LocalCountryFile const & /*localFile*/) {}
-
-    // Called when a map is updated to a newer version. Feel free to
-    // treat it as combined OnMapRegistered(newFile) +
-    // OnMapDeregistered(oldFile).
-    virtual void OnMapUpdated(platform::LocalCountryFile const & /*newFile*/,
-                              platform::LocalCountryFile const & /*oldFile*/) {}
+    // Called when a map is registered for the first time and can be used.
+    virtual void OnMapRegistered(platform::LocalCountryFile const & /* localFile */) {}
 
     // Called when a map is deregistered and can no longer be used.
-    virtual void OnMapDeregistered(platform::LocalCountryFile const & /*localFile*/) {}
+    virtual void OnMapDeregistered(platform::LocalCountryFile const & /* localFile */) {}
   };
 
   /// Registers a new map.
diff --git a/map/features_fetcher.cpp b/map/features_fetcher.cpp
index b74dd6a346..c0b9e6f8dc 100644
--- a/map/features_fetcher.cpp
+++ b/map/features_fetcher.cpp
@@ -78,17 +78,8 @@ m2::RectD FeaturesFetcher::GetWorldRect() const
   return m_rect;
 }
 
-void FeaturesFetcher::OnMapUpdated(platform::LocalCountryFile const & newFile,
-                                   platform::LocalCountryFile const & oldFile)
-{
-  if (m_onMapDeregistered)
-    m_onMapDeregistered(oldFile);
-}
-
 void FeaturesFetcher::OnMapDeregistered(platform::LocalCountryFile const & localFile)
 {
   if (m_onMapDeregistered)
-  {
     m_onMapDeregistered(localFile);
-  }
 }
diff --git a/map/features_fetcher.hpp b/map/features_fetcher.hpp
index 6596816931..dac7ff36ea 100644
--- a/map/features_fetcher.hpp
+++ b/map/features_fetcher.hpp
@@ -75,8 +75,6 @@ public:
   m2::RectD GetWorldRect() const;
 
   // MwmSet::Observer overrides:
-  void OnMapUpdated(platform::LocalCountryFile const & newFile,
-                    platform::LocalCountryFile const & oldFile) override;
   void OnMapDeregistered(platform::LocalCountryFile const & localFile) override;
 
 private:
diff --git a/storage/diff_scheme/diff_manager.cpp b/storage/diff_scheme/diff_manager.cpp
index d11fcd792a..0a36a2b1de 100644
--- a/storage/diff_scheme/diff_manager.cpp
+++ b/storage/diff_scheme/diff_manager.cpp
@@ -95,7 +95,7 @@ void Manager::ApplyDiff(ApplyDiffParams && p, base::Cancellable const & cancella
         result = DiffApplicationResult::Failed;
       }
 
-      base::DeleteFileX(diffApplyingInProgressPath);
+      Platform::RemoveFileIfExists(diffApplyingInProgressPath);
 
       if (result != DiffApplicationResult::Ok)
         Platform::RemoveFileIfExists(newMwmPath);
diff --git a/storage/storage.cpp b/storage/storage.cpp
index 94e081a1ed..12d4949260 100644
--- a/storage/storage.cpp
+++ b/storage/storage.cpp
@@ -284,6 +284,7 @@ void Storage::RegisterAllLocalMaps(bool enableDiffs)
       LocalCountryFile & localFile = *j;
       LOG(LINFO, ("Removing obsolete", localFile));
       localFile.SyncWithDisk();
+
       DeleteFromDiskWithIndexes(localFile, MapOptions::MapWithCarRouting);
       DeleteFromDiskWithIndexes(localFile, MapOptions::Diff);
       ++j;
@@ -927,8 +928,11 @@ void Storage::RegisterDownloadedFiles(CountryId const & countryId, MapOptions op
 {
   CHECK_THREAD_CHECKER(m_threadChecker, ());
 
-  auto const fn = [this, countryId](bool isSuccess) {
+  auto const fn = [this, countryId, options](bool isSuccess) {
     CHECK_THREAD_CHECKER(m_threadChecker, ());
+
+    LOG(LINFO, ("Registering downloaded file:", countryId, options, "; success:", isSuccess));
+
     if (!isSuccess)
     {
       OnMapDownloadFailed(countryId);
@@ -1540,6 +1544,8 @@ void Storage::LoadDiffScheme()
 
 void Storage::ApplyDiff(CountryId const & countryId, function<void(bool isSuccess)> const & fn)
 {
+  LOG(LINFO, ("Applying diff for", countryId));
+
   m_diffsCancellable.Reset();
   auto const diffLocalFile = PreparePlaceForCountryFiles(GetCurrentDataVersion(), m_dataDir,
                                                          GetCountryFile(countryId));
@@ -1577,6 +1583,8 @@ void Storage::ApplyDiff(CountryId const & countryId, function<void(bool isSucces
           if (m_diffsBeingApplied.count(countryId) == 0 && realResult == DiffApplicationResult::Ok)
             realResult = DiffApplicationResult::Cancelled;
 
+          LOG(LINFO, ("Diff application result for", countryId, ":", realResult));
+
           m_latestDiffRequest = {};
           m_diffsBeingApplied.erase(countryId);
           switch (realResult)