[cisco-voip] IPIVR upgrade - what licenses ??

[Fedorov, Konstantin]

Hello,

Its seems simple question but I am a little confused.
Couldn't find answer on CCO.

So.
We have 3 IPIVS 3.1 with 108 ports total, allocated 40-40-28 
Now we want upgrade to the 4.0 IPIVR with the same hardware, but want
reallocated port usage 36-36-36.

What licenses I must order to implement this upgrade ??
What licenses needed if we upgrade IPIVRs to the new hardware. Do we
need base license for servers ??

If some one knows a good link, where explained Cisco license paths ,
will be great.

Thank you.

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Sincerely Yours,
Konstantin Fedorov