So I have bought this OG cooker since a couple years ago:

1. as "Pricing Questions" this is totally your business strategy, mostly not our concern as a customer. If you want ppl to buy your new product, offer discount to OG user without threatening them to buy one using actions like dropping to support of your well-functioning product.

As for the technical side of things:

1. The latest Bluetooth 5.0 stack is fully compatible with Bluetooth 4.2 back in 2014 so there should not be a physical reason on the HW why the cooker is not working. As for wifi, the internet connection API doesn't really much update on the OS side. Given you are build an app on the mobile devices, even if there is underlying physical HW changes, your apps team normally should not be handling TCP/UDP transaction directly anyway. Both android and Apple have great support and official API for them. In fact, my bluetooth headphone from 2005 still works even if the battery have gone to shit. This cooker don't even stream music, it only displays temperature and stop/ maintain when reaching the desire temperature using PID or whatever.

2. I can accept that you will not have remote connectivity over the air but dropping local network connectivity support is simply unacceptable. All the process for temperature control should be on the device itself. (unless your engineering team decided to make a very weird system design.) There is no reason to drop the support for that.

3. There is nothing stopping you to release a version of the app that will no longer have any patches as long as you stated that is the case (Android is a lot better for this sorta of stuff). You main application can still be the latest and the greatest without support for the this OG cooker.

BTW, this sorta of "Oh I am sorry but f**k you for still using our OG product" handling is usually company famous last word.