MIDI– when set to ON, unrealBook will scan for a MIDI interface. (Default is on).
MIDI Send – when set OFF will disable transmission of MIDI messages.
MIDI Recv– when set OFF will disable MIDI messages from controlling unrealBook. (use this to disable listening to the iRig Blueboard).
Expert MIDI – when ON, additional parameters appear in the File->MIDI window. See File->MIDI

Send to Arranger – when ON, will send messages to Arranger.