Krile, let's assume Yobit does not update the wallet for version 1.4, what will happen?
If you have any coins there you should withdraw them before the fork (to be safe at least a day in advance).
Until they update do not use their exchange.
But I am sure they will update, there is plenty of time left. If they don't update till the end of January, I will start using more annoying methods of reminding them to update

I am sure they are not evil, just a bit slow with their support.