My existing CUCM version is 10.5.2 and I am planning to upgrade it to version 12.0.1 SU2. I understand its a standard upgrade and can be done from OS Admin.
Can someone please confirm if my existing version of CUC and CER is compatible with my Target CUCM 12.0.1
or do I need to upgrade these applications in same Maintenance window as CUCM ?
CUC : 10.5.2.10000-5
I've already checked below however its not clear if these applications are compatible or not.
Many thanks for your help.
Thanks Chris for your response, I thought CER 12.0.1 is backward compatible with CUCM 10.5.
I was planning to upgrade CER to 12.0.1 under once maintenance window and upgrade CUCM to 12.0.1 later next week ?
Yes, CER is backwards compatible with CUCM, but not the other way around which is what the original question was about.
So, CER 12.0 would work with CUCM 10.5, but CER 12.0 would not work with CUCM 10.5. Needless to say when you upgrade CUCM you should plan on upgrading CER. But you can potentially upgrade CER without upgrading CUCM.