The MIDI mapping system has changed between MixEmergency 1.5 and MixEmergency 1.6. This new system required a change in the format that was used to store MIDI mappings. MixEmergency 1.6 can import any previous MIDI mappings, and if it does so will create a backup of the mapping file. Because of this, if you are downgrading from MixEmergency 1.6 to any previous version then you will need to copy back your old mapping files.
Once a MIDI mapping file (from 1.5 or earlier) is imported into MixEmergency 1.6 it will be copied into the folder (where ~ is your user/home folder):
If you want to go back to MixEmergency 1.5 with your MIDI control, then you will need to copy the mapping files back into the folder: