Synchronization with Yandex breaks

Good afternoon! I have a Yandex mailbox, I installed several previous versions of the 9.xxx EM client, and on each of them(incuded last one 9.1.2106), synchronization with the server breaks after a random time. Also, after full synchronization (after many, many restarts of the client, which is very annoying), problem happens(break sync), when a letter comes to the server, but the client does not download it until you restart the client. I understand that there is a disconnect. But why doesn’t the client try to contact the server again and again? And why does this not happen on other clients (Bat and Thunderbird)?

Hello, is there any news about yandex sync problem? May be you can tell, will you plan to solve it…some day?