In this directory, there are firmware releases and also release candidates.

Most recent development is in ..._RCn.img files,
 img files without RC are releases.
Most often, there are also changes in web user interface.
Thease are automatically switched,
 if you upgrade from a release to next set of releases,
 i.e. if you change the bnn number.

If you are going to use release candidates,
 please refresh your browser contents.
For Firefox and Chrome Ctrl-Shift-R on a web page does this.

Dusan Ferbas
28th May 2021