Today, the servers that powered the remaining old clients were shutdown. From this day on, said clients, expect for 8.x, will no longer be able to sign on and send and receive messages.
If you want to use 8.x, then you don’t have to worry about a password anymore, as this version also allows for phone logins alongside the usual username/password login scheme. I have a set of build for this version of the client in my archive:
Note that these versions will try to silently auto-update, but to mitigate that, you have to add 127.0.0.1 mra.mail.ru to your HOSTS file. This will prevent 8.x from updating and let you continue using your client.