MultitrackStudio for iPad was updated with several AUv3 improvements. This includes support for recording MIDI from all of the many new AU MIDI apps.
What's new in MultitrackStudio for iPad v3.3:• AU plugins: Options menu ('hamburger' button) now has 'Large View' option.
• AU MIDI instruments that can produce MIDI output now have a 'Record MIDI output (to this track)' in options menu. You can use this to record any keyboards the AU UI provides. This option is enabled by default. (requires iOS 12)
• Significant AU compatibility improvements.
• Songs now remember the Solo buttons.
• Improved support for 11" iPad.