Hi nec,
Thanks for your message!
It always depends on the instrument or effect app manufacturer, what type of IAA connection (audio and/or MIDI) is available.
To learn more, please have a look at our “Limitations of Inter-App Audio” article right here:
P.S.: Please note that many off manufactures have updated their instruments and effects app to the newer Audio Unit standard, which provides much more flexibility in use…
Best,
Lars