0.43b works with existing wallet, thanks. Restore also works great now.
@ThomasV: I'd like to ask if this is normal behaviour or a bug: If i restore, i get full contact list. BUT in case i have older wallet.dat file (with several missing transactions, because i have created them with another instance of electrum on another computer), transactions are synchronized, but contacts stay unchanged.
normally the "restore from seed" procedure adds to your contacts all the addresses to which you sent coins.
I think that this was not properly working with version 0.42, this is why you might be missing some.