update: thanks to @juniper for tracking down this exceptional resource for getting your old mac back on the road. most importantly, has a nice local proxy to get you TLS 1.3 ("Legacy Mac Proxy")
https://jonathanalland.com/old-osx-projects.html
if you’ve got an old mac that has to remain on an older version of Mac OS X, you’ve probably noticed that all of its SSL based internet connections fail.
it’s due to expired root certificates, which you can update for free here:
https://docs.certifytheweb.com/docs/kb/kb-202109-letsencrypt/#macos-ios-etc
just put this 10 year old macbook air back to work as my couch coding machine. it is blazingly fast running 10.9.x (Mavericks) with only 4GB ram and a 1.4ghz i5. for VS Code work it is about as perfect as I could ask for
fwiw: it runs like absolute shit on mojave!