Hi Kirill. I've use Plesk 11.0.9 now. Can i update to 11.5 now? If i update this then does it make any problem? Sorry it's my first update, i really don't know. I've about 25 customer in my server.
Yes, you can. It should work.
We have limited program of test migrations inside TAP program - http://www.parallels.com/tap. If it is interesting for you, you may send me private message (on forum) with your email.