I am running CS6 on El Capitan without issue.
It's working fine here also, I would add however that we have on more than one machine minor issues if we just updated the OS, but if we went back and wiped it and did a clean re-install those issues went away. Also, have to revert to an older version of Java I think helped with Indesign CS6 and maybe Preps also?
I ran some tests on a MacBook Pro. CS6 opened and seemed to run fine, as did CS5 in high sierra. Only tried opening a few files, no real production time put into it, was just curious if it would even open... which it did.
That's encouraging. I may take the plunge and go to High Sierra. There's another OS coming next month from what I heard, and I don't want to go there just yet.
If you want to see an Apps compatibility with and OS or anything else check out the great site linked below. Also I amrunning 10.10 on all our workstations and use CC15 all the way down to CS3 with no issues really. You have to download the old version of Java 6 for CS6 and below but it's an easy find.
The Push To Be a More Versatile Printer
As the printing industry continues to evolve, printers face the challenge of becoming more agile and responsive to meet fast-paced changes in technology and the increasingly varied demands.