Hey there,
I tried the recent El Capitan beta and unfortunately my Apogee Duet stops playback after a few minutes. On Yosemite it is all working well. I already wrote an email to Apogee, I hope they fix it before the final release of El Capitan. If you need special hardware maybe you should do the same and encourage the companies to already start testing with El Capitan. When Yosemite was released, I had to wait several weeks or even months until they fixed it with an update. I had to update the firmware...
So maybe you can give those companies a heads-up
I tried the recent El Capitan beta and unfortunately my Apogee Duet stops playback after a few minutes. On Yosemite it is all working well. I already wrote an email to Apogee, I hope they fix it before the final release of El Capitan. If you need special hardware maybe you should do the same and encourage the companies to already start testing with El Capitan. When Yosemite was released, I had to wait several weeks or even months until they fixed it with an update. I had to update the firmware...
So maybe you can give those companies a heads-up