That means my app has now stopped working on my iPhone 6. The 6 can't be updated beyond IOS 12. The currently installed app, which was working, now tells me it can't work anymore and I have to upgrade it, which I can't do, because the latest app requires IOS 13 or later! Catch-22 in the electronic age, features which you once paid for get effectively turned off. The only thing I will probably really miss is the ability to remotely turn on the climate control, although I used to use it to alert me that it wasn't plugged in and needed a charge at night. The iPhone 6 is now 7 years old and was last sold new 5 years ago. As cars get more like computers, their effective life span could begin to mimic consumer electronics. That is, unless you own a Tesla. Tesla will update the electronics inside your car to the latest version (for money of course) and their app works with IOS all the way back to IOS 10.
