Update for iPad mini

Not all devices have the required hardware to update to the newer iOS. They will not support it. Depending on what version of iPad mini that you have, if you have checked for updates and it shows that it is up to date, that is as far as you can go.

If it does not show an update, then you cannot download one. If you go to Settings>General>About>Model, what do you see there? If you go to Settings>General>About>Version, what do you see there?