I have already migrated the theme to scss and I will work it for bootstrap 5.3 (I will see to force it) So when I have news I will show them
the http://burnaftercompiling.com/nodebb/nodebb-hands-on-theming-guide-part-1/ can't be opened ~ !
Any updated docs for creating a theme from scratch?
I would search at the official documentation: https://docs.nodebb.org/development/themes/
In regards to the support of Bootstrap 4 and/or SCSS, I wouldn't expect anything too soon. See also this issue on Github: https://github.com/NodeBB/NodeBB/issues/5874#issuecomment-380469427