Updating the CRM Client

All,

We are currently in the process of updating the CRM clients on our users PC's to UR11 (Our CRM server is only on UR11)

I have been told that any Client with a UR of less than 6 cannot be updated directly to UR11 and must be updated to UR6 initially. Can someone confirm if true please?

Also, could someone please explain what the RTM (5.0.9688.583) version of CRM client is. Is this the original client install?

Many Thanks,

Elliot