Interrupts on bitthunder

[robertrau]

I am a hardware engineer and have developed a Raspberry Pi Hat-ish board for Quad copters, rockets and RC airplanes. I have tested it using Raspian but need a real time operating system. bitthunder look appealing but I don't see an example using external interrupts. Are they supported? Are there restriction on which GPIO? Have you tried it on a Raspberry Pi Zero? Thanks for any help.
See: https://github.com/robertrau/piflySetupScript
and: http://rau-deaver.org/Project_PiFly.html
I am revising the layout now and want to make sure I can be bitthunder compatible.