I had this situation for a recent upgrade of UCCX 12.5 from 11.5 where the client was using the 300 agent profile. There is a note in the upgrade guide as for some reason Cisco have removed support for the 300 agent profile.
For 100 agents profile, if you want to deploy Cloud Connect, you must configure 14GB of vRAM. For 400 agents profile, you must configure 20GB of vRAM.
300 Agents profile is not supported. Switch Version will fail.
For 100 agents profile, if you do not want to deploy Cloud Connect, there is no change.
Ensure that the reservation of CPU and memory adher to the specifications mentioned in the Virtualization Wiki.
If you look at the other posts there is some debate as to changing the OVA profile and what is supported. Once the OVA is installed you can't change the profile, as in go and tell the OVA to change from 300 to 400 agents. Some say you have to install a new UCCX system using the new profile and backup/restore.
In the case of changing from 300 to 400 the only change is to vCPU 4 and 20GB Ram. This change is fully supported by Cisco for UCCX deployments.
https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/virtualization-software-requirements.html#resize_vm
So I wen't ahead and upgraded the CPU/Memory on the OVA prior to switch version.
There was a worry in my mind after spending many hours reaching the point where I could switch versions that it would fail based on the profile being 300, but worry not the switch version was a success.
As a side note the primary server took just under 3 hours to upgrade, then 2 hours to switch version.
Also note 11.5 to 12.5 is a 2 step upgrade so I went 11.5>11.6>12.5 so its been a long weekend :)
