You must have an active UCSS contract to entitle you to major version upgrades. If you do, you need to place an order through the Product Upgrade Tool which will result in a feature license being issued to you.
What Jonathan is telling you is correct but I'm gonna go a different angle. The best advice I can give you is, unless there is a feature you absolutely must have in 8.0x, then stay with 7.1(3) for now. In fact, I still specifically recommend 7.1(3b)SU2. The first few 8.0 releases have had a number of issues causing several to be immediately deferred. So, course of action I'd recommend:
Stay on or get 7.1(3b)SU2 (if you are at 7.1.5 then so be it)
8.5.1 is scheduled for release late this year - likely this means the code will come out, be vetted a bit, and a stable version of code will start to proliferate early next year - when that happens, listen to Jonathan's advice, and upgrade from 7.1 to 8.5.
The short answer is that you don't.... That isn't entirely true while at
the same time it kind of is, but for the most part you don't configure
the softkeys. You enable or disable them via TCL. Here is the long
answer. Be sure to read the whole thing or e...
Topology: IP Phone > Switches > Microsoft NPS setup to forward 802.1x
proxy to > ISE 2.1 patch 3 Authentication: EAP-TLS using Cisco MIC SANs
Phone Models 802.1X support? 802.1x flavor Addtl Comment EAP-MD5 EAP-TLS
Cisco 3905 Y Y N Cisco 6911 Y Y N Cisco ...
This document describe how DST changes and how time changes are
implemented in DST. Daylight Saving Time (DST) is the practice of
setting the clocks forward 1 hour from standard time during the summer
months, and back again in the fall, in order to make b...