iPhone 6plus
Why my 6plus is on iOS 12.3.1 please help me
iPhone 6 Plus, iOS 12
Question marked as
iOS 12.5.4 is the current version for an iPhone 6 Plus.
If you’re asking why not iOS 13 or later, the iPhone 6 Plus doesn’t have thr necessary hardware for that.
If you’re asking how to get from 12.3.1 to 12.5.4, see the following: Update your iPhone, iPad, or iPod touch - Apple Support
If you need apps that require iOS 13 or iOS 14 (iOS 14.7.1 is current), you’ll need a newer (used, refurb) or new iPhone.
You’ll need iPhone 6s or newer, or a new iPhone.
There are no hardware upgrades available.