How to upgrade to ios14
How to upgrade My iPhone to iOS 14
iPhone 6 Plus, iOS 12
iOS 12.5.7 is the latest iOS security update for iPhone 6 Plus.
Go to Settings -> General -> Software Update -> Download and Install (if you haven't already done that).
iPhone 6 Plus can’t be update to a higher iOS (13 and later).
Yes, most apps require iOS 13.4 or later.
Considering a newer type of iPhone?
Read this before you buy a newer type iPhone.