Pretty much what the title says, I’ve updated my backdrop plugin to version 2.0 (well, 2.0.1 because of a small issue). This version supports the WP customizer so you can see the changes as you make them.
Also in this version of some removals. Since this was re-written some thing are inevitably missing and the way it operates is different. With the old Backdrop it would apply the background to the body element, like themes do. I received a few emails from people wanting to use it to have multiple backgrounds, something that it could theoretically do, but not in practice with most themes. When I was rebuilding the plugin for 2.0 I went ahead and used a pseudo-background element. This means that the background you theme applies is still there, and your backdrop goes over it. That, along with the new options for transparency on the background color, allow you to overlay a new background over your old one.
The plugin has been updated, you should be able to get the newest version here: https://wordpress.org/plugins/backdrop/