magitam

Hey Maureen, I suggest copying everything that’s in your theme right now, into a ‘child’ theme folder (Just copy it on the server, so that the folder is an exact copy, but with the necessary changes to the title, and the CSS file, so that WordPress recognises it as a ‘child’ theme.
That way, when you hit that upgrade button, and the changes are all made, you can just switch it to the child theme.
(If you really want to be safe, copy the theme to a different name/version number, and test it to make sure it works properly, as you need it to, on a backup version of your site, just to be doubly sure, then when you do upgrade, if it doesn’t work immediately with the child theme, then you can switch to the backed up version of the theme that works, and gradually make changes/figure out what needs to be done, and slowly introduce those into the child theme, so that next time you upgrade, it should be relatively straight forward).
Hope that helps! I’m going to be experiementing with Child Themes myself now, to make sure my site doesn’t fall apart when I hit the update button, given I’ve gone and done some customisations myself, and like you have forgotten what I changed/when/where..