I found my old iPhone 3GS is a drawer in 2016. Not only did it still work fine, but it even connected to the App Store and you could still download games I’d had back in the day that werent on the phone, even though those games couldn’t run on any current iPhones. That’s a full seven years after I bought it.
I have an Ipad mini (gsm model) and most of the apps are not working/updating anymore. E.g whatsup, facebook etc. I believe the "mail" app is not working anymore either. I guess the games(most of them) do not depend on the ios sdk so that could be a reason why they still work.
There are two types of compatibility. With the OS and with external network services that may have changed API. You won’t be able to run apps built for later os versions than you have on the device, but these just won’t show up in the App Store for you. Only older versions of the apps compatible with your os.
Things like Facebook and WhatsApp apps depend on the developer to keep the app compatible with their network API. I would expect mail to still work, depending on which service you use. Any custom hooks into GMail for example might fail if Google changes the back end interface.
The apps themselves should still ‘work’ as in run on the device just fine as they were built for that OS, it’s compatibility with external services that may have changed their APIs that is the main issue.
In practice Apple forces the developers to use only new APIs(available on new OS) while the device is not supporting new OS updates.
Submissions with the old APIs are no longer accepted so tell me, isn't that planned obosolence?
Basically I as a developer and owner of the device cannot update my own app, on my old device anymore because the OS does not support the new APIs and Apple does not allow me to submit updates with the old APIs or to upgrade the OS.
Your only choice is to not use Apple APIs that are changed often. In practice you can do that only on certain games or niche apps.
Planned obsolescence my arse.