My Customer have a CallManager 7825I2 configured with the version 5.1.3 and I would like know if is possible to do upgrade to version 7.x or 8.x.
It might not be supported for version 8 according to Cisco Compatibility Matrix at
Looking under note 5 at the end of the page, seems like only bridged upgraded is supported.
If you go to version 7 a memory and/or disk upgrade may be mandatory for support, but your client probably will have to spend more money to upgrade again to v8 and on hardware. If it's possible for the client to get new MCS bundle quote and compare prices a better decision can be taken.
Also, keep in mind age of hardware and if it's advisable to replace it as it ages. There is no rule to it, depends if you have redundancy, support contracts for the client's servers.
This is the "master" list for Server support, which does show support for your box in CUCM 7.(x). I would be leery
for 8.(x) as the server support list is not fully fleshed out yet;
Supported Cisco Unified Communications Manager Releases by Server
Hope this helps!
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