Sorry for the delay guys, we've been all wrapped up in meeting Owlboy deadlines and traveling lately, but the new update is finally live for Mac, and it should work for the new El Capitan OS.
The changes are the same as the PC version, but here's the list nonetheless:
Change list:
I will also try to get the Linux update up and running ASAP(hopefully within the weekend).
If you experience any issues with the update, plase feel free to get in touch at support(at)dpadstudio(dot)com or post in the Steam community :-)