iPad Air2 can't update iOS from 12.5.1 to 14

A first generation iPad Air, iPad mini2 and mini3 can only be updated to iOS 12.5.1. With iOS 12.5.1 installed, you must have one of these three models.

Not sure which iPad you have? Identify your iPad model.

Apple ended major update support for these models of iPad in September 2019 - although they since continue to received “point” security updates. These devices cannot be updated to iPadOS 13 (or any later major versions of iPadOS) as the internal hardware does not meet the minimum technical requirements (CPU and RAM) for newer versions of iOS/iPadOS.

Some App developers have dropped support for iOS versions preceding iOS 13.x for technical reasons (often because APIs or software libraries upon which they rely have been updated in the new version of iPadOS, making their App incompatible with earlier versions). 

Whilst many App titles remain compatible with your iPad, if you want or need to access to Apps requiring the most recent versions of iOS, you’ll need to consider replacement of your iPad with a newer or current model that supports iPadOS14.

Sorry, I appreciate that this may not be what you were hoping to learn.

I hope this information provides helpful clarity as to your available options - and the limitations of your existing iPad Air.

Perhaps it is an iPad Air 1st generation (check this codes on your device's back cover: A1474 or A1475 or A1476.

Should be this case, it cannot support iOS versions beyond the one that's currently running on it, because of hadware incompatibility, sorry.

Regards

Giulio

You’re very welcome.

Before condemning your iPad, perhaps consider that whilst Apple have ended major update support your iPad, it continues to receive “point” security updates. Your only real issue, at present, is compatibility with Apps that require update to iPadOS13 or later.

You are most welcome (sorry I had to give you bad news).

Take care.

Giulio