When I upgraded to 2013 from 2011, in "System Check", show error: "The product key is not compatible with the installed version of Microsoft Dynamics CRM".
The product key is commercial, and even I used the trial key from 2013 download page, the same error.
In second "Issues that are resolved in Update Rollup 2":
When you use the Upgrade Wizard, an error message is shown with a red flag in the System Checks window: "The product key is not compatible with the installed version of Microsoft Dynamics CRM"
So, it looks like the rollup2 already fixed this issue.
But, the 2013 download page provide only RTM version, not integrade with rollup 2. And, in my case, when I installed 2013, I selected "Get updates for Microsoft Dynamics CRM", and it will show "not update needed".
Any suggestions? Thanks.