CUCM / CUC / CER / IM&P compatibility

[tachyon05]

I currently have CUCM version 9.1.2.13900-10, CUC version 9.1.2.13900-621, CER version 9.0.2.10000-1, and CUP/IM&P version 9.1.1.61900-7 running on UCSC-C220-M3S hardware.  My understanding is I can upgrade any one of these apps to version 11.5, and maintain compatibility with the other apps running in version 9.x.  Another words, I can upgrade CUCM for example to version 11.5, and it will continue to work with other UC apps I have running on version 9.x (until I get around to upgrade them).  Is this accurate?  I can't find any documentation on this. 

[Jaime Valencia]

No, that's not accurate. That would only be true for CUC.

The upgrade guide and/or RNs for each product contain the compatibility information, assuming the product does not have a dedicated document for compatibility.

That's the documentation you need to review in first place before planning any upgrade. 

[tachyon05]

Ok Thanks.  My goal is to upgrade the entire UC from version 9.x to 11.5.  I prefer to upgrade one app at a time to minimize the number of systems that will be down/impacted.  Additionally, I would like to spread out the upgrades into different maintenance windows as opposed to upgrade the entire UC all in one window. 

Based on my research, it looks looks like

CUC version 9.1.2.13900-621 works the newer CUCM 11.5

CER version 11.5 works with the older CUCM 9.1

Would you recommend or confirm I can do the following?

1) upgrade CER to 11.5,

2) a few weeks later, upgrade CUCM and IM&P to 11.5

3) a few weeks later, upgrade CUC to 11.5

[Jaime Valencia]

Yes, that would be a supported path for your products.