Fully updated and running High Sierra flawlessly.
What year is it? Can you run Linux on it?
It has the year in the attachment. You just need to click on it to enlarge it.
Missed that. I had the same machine (but with only 8 gb RAM and an i3 processor), and it runs Ubuntu and Arch flawlessly. (Those were the only two distros I tried.) Excellent computer with a particularly nice display.
If you haven't already done so, I suggest that you post this on Kijiji. That's where I found my 2011 iMac. If you do so, consider posting it on the GTA version as well as the Peterborough Area; broader coverage.