Ring app not working due to iOS restrictions

I use a MacBook Air latest iOS is 12, the latest Ring App needs iOS 15. I had a recent message from Ring to update my device, I can no longer access the app on this device. I have decided to cancel my Ring doorbell plans for this reason plus the hike in subs. It is a shame because the operating system is at the moment the best. I expect to eBay the equipment when the current plans run out in July, perhaps something better and less expensive will be up and running by then.Regards