I have a few IOS devices, you know what prevents me from using them? It's not the battery, its the lack of OS updates. I can't install new certificates, or get

I have a few IOS devices, you know what prevents me from using them? It's not the battery, its the lack of OS updates. I can't install new certificates, or get access to app stores. They're useless. In fact, the lack of a replacement battery has never prevented me from keeping something working, only software or physical damage.