So, we have a custom theme built with the SiteOrigin Page Builder. Until recently this has played somewhat nicely with Wordpress 5. A recent update to Advanced Custom Fields has more or less completely broken our ability to edit the site's front page. So, I would like to take us back to WP 4 keep us there for as long as practically possible.
Our production site is still on the old code base, but every time I have moved the site I have been forced to upgrade, which then introduces all of the breaking changes again.
The functionality we need is broken with or without the Classic editor, so shy of going on an extensive bug hunt which is above my level, rolling back (if possible) is the only option I really have.