I use the Ipad Pro, Yamaha Motif XS for the Midi control and "Songbook + Version 3.3.4" for display the text.
Unfortunately, the contact between the Ipad and IRig Midi II turns off between a short time.
If I unplug the Lightning Conection Cable and turn it on back again, it will work for a while.
What could happen? Could it be a wrong Midi Controller at the and of an Midi File, or a Setting in the Songbook+? I don't know!