Bento Openbox Remix 20.04 core 5 is the latest Ubuntu Openbox Remix version available.
The installation image is 734 MB large, and reducing the size below 700 MB is now proving difficult. Also, Ubuntu no longer provides versions for older computers equipped with 32-bit processors.
However, Ubuntu is still a very good choice for an easy use on most computers, and thanks to the LTS editions, can allow keeping your installation always up to date.
To get it, go to the Downloads page.
/!\ This very stripped “core” version is intended for users who prefer minimalism, so if you would rather want an edition fit to use “out of the box” with many codecs and applications for everyday use, you will prefer either an official version or one of the community editions supported by Canonical.