How to update my iPhone 7 Plus to latest iOS version
update
[Re-Titled by Moderator]
update
[Re-Titled by Moderator]
The iPhone 7 Plus originally ran iOS 10. You can update it to the latest version of iOS 15 (currently 15.8.3).
About iOS 15 Updates - Apple Support
You cannot update it to iOS 16 or higher. For that phone, iOS 15 is the end of the line.
The last and final update for the iPhone 7 Plus was iOS 15.8.3
Tap Settings > General > Software Update
What does the message say there?
The iPhone 7 Plus cannot update to iOS 16, 17 or 18 if that might really be what you are asking about here.
iOS 15.8.3 is the highest an iPhone 7 Plus can be updated to. It lacks the hardware to be updated any higher. If you need higher level iOS versions, then you'll have buy a much newer, more modern iPhone.
How to update my iPhone 7 Plus to latest iOS version