My iphone just updated to 12.5 and it says no more updates. How do I get it to update to 14.0?

If you have an iPhone 6, you can’t update further. If you need a newer iOS version, you will need a newer phone.

An unit running 12.5 through 12.5.2 isn't capable of 13 or above.

(195057)

See this list for explanation: