> Within two years most apps will probably stop supporting iOS 15 so you’ll start having issues.
Some might, but I don't think most will, and I feel overall there's a fair chance they may not run into many problems. Let's look at the top 20 apps' iOS requirements for their latest app version:
- ZOOM - iOS 8.0
- TikTok - iOS 10.0
- Disney+ - iOS 14.0
- YouTube - iOS 12.0
- Instagram - iOS 12.4
- Facebook - iOS 13.4
- Snapchat - iOS 12.0
- Messenger - iOS 11.0
- Gmail - iOS 13.0
- Cash App - iOS 13.0
- Amazon Shopping - iOS 13.0
- Netflix - iOS 14.0
- Google Maps - iOS 13.4
- DoorDash - iOS 14.0
- Spotify - iOS 13.0
- Widgetsmith - iOS 14.0
- WhatsApp - iOS 12.0
- Venmo - iOS 13.0
- Google - iOS 14.0
- Google Meet - iOS 13.0
So 7 of these apps can have their latest version run on the iPhone 5S (iOS 12), which released nearly 9 years ago and hasn't received a major update in almost 4 years. None of these apps require the latest version of iOS, and only 4 of them require the second most recent version of iOS.
However, many if not most of these apps will allow you to download an older version if you aren't running the latest iOS version, and it will often continue to work. Realistically, most people probably won't care if their Gmail app is running an old version if it still works.
> It’s obviously served you great, but it might be time.
If it becomes an issue, they can upgrade at that time if they feel it is necessary. I don't see any reason to upgrade prematurely though.
Yes, in theory their device will be insecure once it stops receiving updates. In practice, I'm aware of exceptionally few people who have been infected by a virus on an unsupported iPhone. They can disable JavaScript in the browser if they want to be extra secure (not that that mitigates all vulnerabilities, but unless they're notably rich, famous or powerful, they're probably unlikely to be targeted.)