Some good news, and a question
It would appear Apple has not been clear cut as to whether or not drivers that work in 10.10 will work in 10.11. However, in at least one instance a driver that has not been updated through the App Store software updates from Apple a printer does appear when you Option click add driver through the System Preferences in El Capitan. Apple has this listing of 10.6 and later drivers available through software update. Apple support downloads for vendor specific drivers exist for HP (Jun 18, 2015), Ricoh, Canon (Sep 15, 2015), Canon Laser (Nov 3, 2015), Epson (Jun 8, 2015), Brother (Oct 8, 2015), Lexmark (Jan 29, 2015), Samsung (Nov 14, 2014), Fuji/Xerox (Apr 16, 2015)where the dates are the dates the driver was last updated on Apple Software Update. My Canon Pixma 922 drivers, which are clearly not related to the Laser drivers work just fine when I option click the add driver in the Apple menu -> System Preferences -> Printer and Scanners in El Capitan. Furthermore, when I go to select Options on drivers, I get this dialog:
None of these printers would appear to have anything to do with my Pixma.
I wonder how many other drivers from prior to September 30th work on El Capitan?
iMac, OS X El Capitan (10.11), * I may get paid from macmaps links