Sysex on Taiwanese iOS?

This is a weird one that perhaps someone has seen or has ideas about.

We have a JUCE-based companion app that connects to our device over BLE MIDI using MIDI Sysex messages.

Users in Taiwan (and so far, only Taiwan) are reporting that on iOS (all versions of the OS and our app/firmware are current), our app is unable to establish a connection with the device using the Sysex messages that work everywhere else. We’ve verified that iOS reports that the device is connected over Bluetooth for these users.


Though I can’t offer much direct help, this is a curious puzzle! What version(s) of iOS are your Taiwanese users experiencing this on?

Current versions of the OS and our companion app. Works correctly on an iPhone 8 they have (so we know the device is working as expected, and it also sends MIDI voice messages to e.g. GarageBand), inoperative on the iPhone 12 models they wish to use.

I hate these “that’s not possible!” bugs the worst.

Did you try changing your test device(s) locale?

While you’d might need some translation app on another phone to scroll through, I’d expect you’ll have better simulation of the behavior.

I suspect this as there might be differences (or bugs) with a locale: