Hallo My phone is left on the old update please see the problem please fix My phone

The iPhone 6 and 6 Plus cannot update beyond iOS 12.

~Lyssa

There is nothing to fix on your phone. It is now too old, too under powered, no longer supported and lacking the required hardware to update past the current iOS version on your phone.

If you need the newer iOS versions, it's time to retire your now 7 year old phone and buy a newer more modern phone which can run the newer iOS versions.

iOS 12.5.2 is the highest version that can run on an iPhone 6 series.