Detailed Release notes may be found here:About MainStage 2.1.3
This update improves overall stability and addresses a number of minor issues, including the following:
Fixes an issue where presets for Audio Unit plugins were incorrectly displayed.
Addresses an issue where incoming MIDI was forced to channel 1.
Resolves an issue that could cause MainStage to quit unexpectedly when using Undo after deleting a patch.
This update is recommended for all MainStage 2 users.