Sync non-upgraded Notes between macOS Sierra, Yosemite, and iOS 9?
Most of my Apple computers still run Yosemite and will continue to run ONLY Yosemite for some time to come because of professional pro audio software compatibility and some other issues (this will not change any time soon.)
My iPhone 5s does have iOS 9 and I totally rely on being able to sync Notes on my iPhone with Notes on my Macs. I did NOT "upgrade/update" Notes on my iPhone to the newest format. If I had done that, I believe my Notes app on my iPhone would forever only be able to sync with El Capitan (which I've skipped altogether) and later.
My questions are:
1) Can I install macOS Sierra on one of my Macs but still opt to NOT upgrade/update my Notes app so that I can still sync notes with my Macs that are still running Yosemite? Or does Sierra REQUIRE Notes to get updated to the newest version with no option to opt out?
2) Same question for iOS 10 (which I won't be running until I get an iPhone 7 eventually)....Does iOS 10 still allow a user to opt out of this upgrade/updating of Notes to the newest format? Or is the new Notes format a REQUIREMENT of iOS 10?
Thank you for helping!
iMac, OS X Yosemite (10.10.5), 32 GB RAM