--backup-dir-dels breaks compatibility

[Tomasz Chmielewski]

I wrote a script that uses rsync a bit and wanted to use it. While testing
was fine, the real life was more complicated :)

Basically, my rsync command looks like that:

rsync -v -azu -b --backup-dir /var/backup/files/ /var/profiles/files/
username at host:/


When I execute it where both machines have rsync 2.6.3, everything runs fine.

When I execute it on a machine with rsync 2.6.6, and the remote machine
has rsync 2.6.3, the command fails:


rsync: on remote machine: --backup-dir-dels: unknown option


This is weird to me, as I didn't change the options, and I don't use any
"--backup-dir-dels" (which is not documented in the man by the way).


How can I get around this problem? I can't really update rsync on all
machines.


-- 
Tomek