Update 3 for SP2 or SP3 client + SP2 DB

Hi,

Is Update 3 the latest update for NAV 4 SP2 client, and where can I find it?

Also, can NAV 4 SP3 client be used to work with SP2 database?
I tried to do that, and after starting the client and opening the database, there was a question to update the database. I confirmed, and when after few seconds process was finished, database was opened and everything seamed to be OK. But, I did not tested it in detail, so if anybody knows for some problems with this combination, please speak up...

I want to use newer client but without database upgrade, because I do not have time to do that right now (to much customizations).
Reason is, synchronization of user permissions. I use SQL Server 2005 as a development platform and i have created all needed sql logins on the server. But, when I try to restore database Navision freezes when it tries to create users in the database. Then I stop the process, start NAV again, go to Security and try to synchronize, but i get error that says "User XY does not exist in the database". I must manualy create user in the database to make it work. Also, sometimes even if the user exists in the database this message pops up.

Please help!