I dug up this older post because I now have an iPhone 12 Pro. After I finished setting up everything, I decided to try connecting it to my DCS wifi. I made no changes to the phone parameters, the app settings or the wifi. I connected the phone to the MTH_DCS wifi. I opened the app and started up #1 locomotive which is a Legacy SD70. Everything worked exactly as expected including the quilling horn. I then started and ran 7 other Lionel and MTH locomotives with no problems.
Some details:
- the wifi is set to MTH and is not part of my home wifi
- the MTH wifi is using channel 7 (set using LuCi) because my home wifi is using channel 9
- iPhone is running iOS 14.3.3 Beta. Current iPhone 12 ships with iOS 14.2.1 which is the current user version.
I don't know if this helps anyone but, despite the MTH app not being updated, it continues to work properly with the newest versions of iOS.
I also checked out the Lionel Icab app and it, too, functioned as expected.