The MIDI issues have been resolved in version 3.0.1. If you are still experiencing problems with MIDI and Flashnote Derby, first confirm that your MIDI is working properly with other music apps that you might have. Then, go to the App Store on your device, choosing Updates to see if you have a Flashnote Derby upgrade available to you to install.
If you are certain you are running the latest version of Flashnote Derby and are still having MIDI issues, please let me know by raising a support ticket.
An issue has bee identified which may cause MIDI to stop functioning, even if it had been working at one point in the past. A pending app update will fix this issue. If you have app updates set to automatically download on your iPhone or iPad, you should automatically receive the update when it is available.