Upgrade 101: Do I need to upgrade sequentially?

I installed 8.6.4 a few months ago and there’ve been a number of versions of core that have come out since then.  I want to upgrade, but do I have to do it sequentially?  Like, first do 8.6.4 to 8.6.5, then to 8.6.6, etc., or can I just back things up, overwrite with 8.6.newest, and then copy back in the key parts of settings.php or .htaccess and it should work?

I have tried to get composer working and looked at drush, but for various reasons this isn’t working.  Am opting to just do the manual upgrade — but hoping I don’t have to do this one by one by one.

Thank you!

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