i have just bought an i mac with el capitan and had my cs4 and cs6 along w/ the new osx transferred to an an external ssd and had no problems w/ the change they both worked well, kept the cs4 for the nik filters until i down loaded the free version to cs6 and eliminated cs4 and all is fine ....................what the hell back it up and if it doesnt work you can always reload it back to its original system ..................hope this helped
d.