Q: iPad mini will not update

The 9.3 update is temporarily on hold - so please stick with 9.2.1 for the moment

The "list" of pertinent articles as I know them to be as of now

- you can read about the problems in these articles, and possibly find workarounds, particularly in the last one

If you can't activate your iPhone, iPad, or iPod touch after installing a software update - Apple Support

Apple pausing iOS 9.3 updates for older devices, working on activation fix | iMore

Apple releases new build of iOS 9.3 for users of iPad 2 affected by bricking bug | 9to5Mac 

Apple Addresses GSM iPad 2 Activation Bug With Revised iOS 9.3, but Broader Issue Remains Unfixed - Mac Rumors

If you can’t activate your iPad 2 (GSM model) after you update to iOS 9.3 - Apple Support 

Troubleshooting iOS 9.3 Update Problems

From a post by: ChitlinsCC