Unable to update to iOS 14.2

I am currently using an iPhone 8 Plus that is on iOS 11.2.5, I am unable to do the 14.2 update and im not sure if it is because of it being too out of date on its update. Any Ideas? Ive tried using a different network, it has 48GB of space free, and ive tried using a pc but it says unable to complete update "Error: 4000".