How apply patch updates

I’d like to upgrade an install of 1.8 RC-1 to RC2 and also use the latest patches you’ve released on Github for this.

Can you please advise the best method to apply these? Is it as simple as overwriting existing files?

Please have a look here -
If you’re using docker then upgrading via launcher is also described there (link under Docker installations)

As for the changes made after rc2 release, you could merge it yes, but it might be better to wait for 1.8.0-rc3 release.

I would caution against overwriting the files - you may get a change you don’t realise you’re getting which breaks something else (because it has an associated change somewhere else).

The best thing to do is wait for the release as Peter suggests - or to take the entire develop folder. Please keep in mind that if you do this you will be running unreleased code.