Apple Support for older OS???

[swandy]

My wife's iMac (mid-2011) is running High Sierra and from what I see cannot be updated to Mojave. (Not a big deal as she does not use it much - uses her iPad and iPhone more.)
My question - as I just updated my Parallels install of Windows 7 to Windows 10 because of MS ending support next year for the older OS - is how long does Apple traditionally keep supporting and updating their older OSs?

 

[CoastalOR]

Apple supports older OS for 3 years with security updates. High Sierra (10.13) was released in Sep. 2017 and was superseded by 10.14 in Sep. 2018. I would expect HS to see Apple support until Sep. 2021.

 

[Fishrrman]

My opinion only:
Apple may stop "supporting" older OS's.
But I just keep using them anyway.
If they work.... well... they work.
If it's the only OS that runs on your hardware... well... "use what you have."
Don't worry about it being "out-of-date".
If it runs, it runs.
If it breaks, it breaks.

That's life.