I have a WiFi to Serial accessory that I'm using with an iOS app.
I was able to use it properly until iOS 12.
The app requires both Wifi (to collect data from the accessory) and Cellular (to send data to the cloud) to work. I can get either WiFi or Cellular to work separately but not at the same time except that I can access the accessory settings page over http with Safari (but not with the app over TCP). The app is using GCDAsyncSocket library for requests to the accessory.
I've been able to get things work randomly by disconnecting the WiFi network, reconnecting it and set set WiFi assist on/off but I think that there should be a way to get things working properly.
What exactly changed on iOS 12 to get things broken?