Hello @labcoatguy,
To upadte a theme without waterfall - support you need to download and install it by yourself. I believe all non-waterfall-theme dev’s email their customers when a new version is available.
Except you bought a theme while a maczot (or a compareable) sale. Then you need to download the theme from there.
Custom changes you’ve made need to be included in the new version by hand, but do not forget to create a backup (right-click on the theme -> duplicate).