Sending MIDI from iOS IAA app

Does anyone have any suggestions on how to enable sending MIDI from an IAA app (instead of just receiving MIDI) in iOS? Plugins where I’ve enabled Plugin MIDI Input and Plugin MIDI Output work just fine when run as AUv3 in AUM and apeMatrix, but when I try the same with the IAA version of the same plugins, AUM and apeMatrix report that the plugin can only receive MIDI, not send. As I’m trying to write some sequencers, MIDI output would be quite useful. Or is this not possible with IAA apps?

Thanks in advance for any help.

After doing some digging, I still haven’t found a way for an IAA app to report itself as a MIDI output generator (so the app could show up in the top row of AUM’s MIDI patchbay), but I can get MIDI out of the plugin by identifying and opening relevant available MIDI outputs (like AUM’s virtual MIDI input) and sending MIDI data directly there, and make whatever further MIDI connections I need to make using the AUM input.

Sorry, but we’re not going to put any effort into investigating this. Apple has deprecated IAA so the future-proof way forward is to create an AUv3.

https://developer.apple.com/documentation/ios_ipados_release_notes/ios_ipados_13_beta_4_release_notes?language=objc

Fair enough; I didn’t know (or hadn’t noticed) about the impending deprecation of IAA.

My plugins work fine as AUv3s, including with MIDI; the appeal of IAA in my case was being able to have a full screen interface, control the host’s transport, and easy enough to navigate back to the host (as per the JUCE IAA examples).

Is there a trick in iOS to having an AUv3 ask to launch its editor as full-screen, or in as big a window as possible, or is that entirely up to the host?