License validation and error reporting
The one-click upgrade system works using a special API endpoint (unrelated to our REST API) which is authenticated by a special API key which is included in your XF 2.1 downloads. At the same time as checking for updates we check a few other things as well.
An example of some of the errors and warnings you might (but, hopefully won't 
) see is below:
[ATTACH=full]187072[/ATTACH]
[ATTACH=full]187073[/ATTACH]
[ATTACH=full]187074[/ATTACH]
[ATTACH=full]187075[/ATTACH]
Clearly some of these issues are significant, and apart from the license expiry notification (which is purely informational) may potentially indicate license agreement breaches. That said, these are mostly to help in avoiding some of the genuine mistakes that customers sometimes make with their licenses, such as re-using the same downloads across different installations.
