We have an app that has been around for 4 years now. We have stopped targeteing older versions with updates - first iO6 to 7 and then iOS 9 to 10. The older versions work fine on the older devices and are available to customers, who have gotten the product (we sell hardware, the app is free.)
But new customers have a real issue if they cannot upgrade to iOS 10. We are getting calls every week about that. We used to be able to direct them to get the app on iTunes for macOs or Windows, but that option is gone.
Apple really should fix this. We have some unhappy people out there!
How do others vensors solve this? Any other ideas?