Hello and welcome.
Officially, it was designed for compatibility with OS X Leopard 10.5 and Snow Leopard 10.6. CS6 was designed for OS X Snow Leopard 10.6 thru Mavericks 10.9 on Intel Macs. Some folks have reported that ti is mostly functional in El Capitan, but it requires Java Version 6.
If you really want to upgrade to El Capitan with full Adobe Creative Suite compatibility, then I would recommend running Creative Suite 2015.1 or later.
C