I have a mid-2012 vintage Macbook Pro with a 2.9 GHz Core i7 processor, currently running MacOS Sierra (10.12.6). Not having seen any software or security updates for a year now (as anticipated), I’m wondering if I should try to upgrade my OS at this time. It’s the last model with an optical drive and non-retina screen, and I installed an SSD in place of the original hard drive approx. 3 years ago.
If I were to upgrade, what is the latest version of MacOS that is not only compatible, but will work efficiently and not require me to replace the older apps I’m using? What diagnostics should I run in advance to make sure the system is robust enough to go through a system upgrade? Generally, everything is working well now and I don’t want to 'rock the boat’ any more than necessary. I regularly upgrade Zoom, Safari and Firefox, but not much else, am perfectly OK with Office 2011, and don’t care about rapid syncing with other devices, ‘dark mode,’ nor other bells and whistles featured in later versions of MacOS X.