I have used Roundcube for awhile now and it works great...
But I see you say that the DB should use UTF-8, any reasons for this? ( I have never used UTF-8 for the db and never had any problems...)
Also, when upgrading from an old version, there is nothing in the db that I need to preserve? I can start with a fresh db without loosing anything? (except for address book?)
Regards,
BTJ