If you're too impatient to wait for even developer releases, you can get the current version of the filer and other programs directly from subversion.
This is the version that the developers are actually working on at the time.
ROX-Filer has moved from subversion to git, so see the git instructions instead. The other components are still in subversion for now.
You can view the repository contents online here.
To checkout a module (e.g., Edit) using subversion, use this command:
svn co https://rox.svn.sourceforge.net/svnroot/rox/trunk/Edit
For more information on using subversion, see the SF.net instructions.
If you don't have a subversion client, you can download the daily snapshots instead. These are generated at around 0710 each day (UK time) from https://rox.svn.sourceforge.net/svnroot/rox/trunk/ for each application, except for ROX-Filer which is now generated from the primary git repostitory .
To get a complete system, you also need to create Manual.html from Manual.xml (by running make in the src/Docs directory) as well as recreate the various language translations. These files are not in subversion because they are generated from other files.
However, the daily snapshots do have these files included.