I have small separate 3.5 and 4.0 View environmnets. Is it possible to upgrade only the Connection/Security servers to 4.5.1? Would this require any changes to the View Agents or Clients?
I don't think your environment would be supported but from a functionality standpoint the client would probably work. The agent i think would depend on if you were deploying linked clone pools.
I assume you mean 3.1 clients, since View went from 3.1->4.0? Yes, they can still connect through a 4.6 connection server - I'm not sure if it's officially supported now but the basic authentication to the broker, tunnel to the security/connection server, and RDP connections to the desktop will work.