I'm a relatively new user to your app and absolutely love it! I'm a gigging musician that uses an XR12 as a submixer primary for my IEM setup but also to control what I send to our board, which is sometimes an XR18 but many times, analog boards.
I'm also UX/UI developer, professionally so I'm keen to discover new products like this one. One repeatable bug I discovered is when downloading a layout from Google Drive. I can share the file to the Drive with no issues, but when I try to import one by pushing the up/down arrows in the top right, the app immediately quits. It's repeatable, whether or not I'm connected to the XR or in offline mode.
I have the app in 4 different devices, iPad Mini (version 1, running 9.3.5), iPad 2 (also running 9.3.5), iPhone 5 with 9.3.1 and a iPhone SE really running 12.1. The only one that works without crashing is the iPhone SE on 12.1.
There are many other things that I could suggest to improve the design and functionality of the app but for a 1.0 version, it works amazingly well and is quite stable on my older devices. It's given me no trouble at all for the 2 Live gigs I have used it with. As a developer myself and musician who plays out at least twice a week, I would welcome the opportunity to act as a beta tester if you need anyone else.
Keep up the great work!
Mixer Model: XR 12
App Version: 1.0 (16)