Right click stops working after OS upgrade

After installing El Cap on my iMac 27 in (late 2013), right clicking on the magic mouse no longer works. I've tried every fix noted in previous discussion threads to fix the issue (checking the relevant box in sys prefs on and off, every possible combination of restarts, deleting magic mouse plist files. Nothing works. Losing the functionality of the right click is driving me crazy. Yes I know I can hold the control key and still get the functionality, but I need my right click!

Coincidently, the "touch to click" function of the trackpad is also gone. Since both of these devices are bluetooth, does it point to a bluetooth problem? Is it a hardware glitch? My gut tells me it's software since it happened along with the upgrade to El Cap. I recall the same thing happening last year when upgrading from Yosemite to Maverics (or was it the other way around?), but I can't recall what finally fixed it. I've gone back to all those threads and tried those fixes to, but still the same loss of right click and touch to click.