KLCP 10.0.3 doesn't let to choose subtitles in MKV

With KLCP 10.0.3 I cannot to choose the needed subtitle in .MKV file while using of LAV splitter. Earlier I use Navigate->Subtitle Language etc.
What is it, bug or feature, and what I have to do with it?
P.S. Haali splitter never let to choose subtitles in MKV, so LAV was the last and only hope and now it dead

Don't worry. All functionality is still there. It has even been improved!
The stream selection has been moved from Navigate menu to the Play menu. The selection is now unified, meaning it shows both embedded and external audio/subtitle streams in the same menu.

Stream selection works fine with Haali splitter as well. Both from MPC-HC and through the tray icon of Haali splitter. It seems that you are unaware of the existence of the tray icon. I think you might also find that useful. LAV also has a tray icon. You can find the tray icons in the bottom right corner of your screen during playback. The is referred to as the "system tray" and "noticifation area". Windows may hide icons by default, but you can expand it by clicking on the triangle shaped button.

In the Windows control panel you can find options to always show certain icons in the Notification Area.

Thank you for the extremly prompt answer. You are right I never use tray icons, only look at them to see which splitter works at the moment. You are right as well that all functionality is there, but it seems to me it is more convinient to use right-click in any part of the picture instead of pointing Play menu, particularly in Full Screen mode. Don't you think?
After all I found 10.0.3 very accomplished. Thanks a lot!

The contents of the Play menu is also available when you right-click on the video.

Of course it is! I found out all about the new features of the KLCP/MPC-HC interface. Now I have to lose of habit to use Navigate for .MKV, that's all. It isn't difficult to be used to go through the Filter. It is even more convinient and uniform. So the 10.0.3 is the best so far!

You can also switch subtitles by pressing S. And switch audio by pressing A.