Cant upgrade UCCX from 11.6SU(2) to 12.5SU(1)

[OrBaram]

I am trying to upgrade a UCCX server node.

 the iso file im using is: UCSInstall_UCCX_12_5_1_UCOS_12.5.1.11002-481.sgn.is

I get the error message: 

Error encountered: "The selected file is not valid. Please ensure that the COP/ISO file is intended for this release. MD5 Hash Value: - " 

the md5 hash is the same as the one that appears in the document from cisco

the MD5 is: 61f89437a5e5927db2d5173c36fdce4e 

anyone knows why? 

Thank you very much!

[Roger Kallberg · Accepted solution]

Have you installed the pre-req files?

[OrBaram]

hello roger!

thank you very much for your detailed and specific answer

you are the best 

have a good day