I'd really suggest you give your local Cisco partner a call. They'll be able to walk you through the whole process of evaluating both your software and hardware needs in relation to your business requirements.
I know that's a cop-out answer, but without very specific business/technical background/requirements it's pretty hard to answer your question in an online forum like this.
I really appreciate your quick response. The challange I'm actually facing is not on the hardware requirement. The challange is that it is not clear to me the licences, support contract etc that I need to purchase for the upgrade. If you have information on this you can provide, just assume that there is no hardare limitations.
Are you up to date on all your support and maintenance contracts (SMARTNet and ESW)? If you have a current ESW contract you should be able to upgrade for free. If you e-mail firstname.lastname@example.org they can verify your coverage (by providing serial or contract numbers) and provide you the licenses you need to process the upgrade. They will simply look at what your current rights are and give you the 7.x equivalent.
I have to repeat though: Engage a Cisco partner to have this discussion. This forum can give you advice and guidance but what you're asking is like asking us to help you pick what color to paint your house without ever having seen it. Bad metaphor but upgrading CallManager is NOT a DITY job!
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...