Well, I added midi update to version upcoming 32. GUI will be not available yet, but you can define midi options in expert setting
this will be necessary to add:
[midi]
mpu401=intelligent
mididevice=default
mt32.thread=on
mt32.romdir=/storage/emulated/0/ROMDIR
mt32.analog=2
mpu401 set to none or intelligent
mididevice set to default or mt32
mt32.romdir is directory in which are stored midi ROMfiles
#analog means quality, 0=fastest,2=good middle