Ubuntu provides an older version of parallel - suggestion to retrofit my usage?

[John]

Ubuntu 12.10 seems to be providing GNU parallel 20120422.  I am trying to run a 
script that uses features that are apparently contained in a newer version.  
The code to the script can be found at the link below, but I think that this is 
the main part:

parallel -k do_clean ::: "${toclean[@]}" 2>/dev/null

Can someone suggest an alternative invocation of parallel so it works on the 
20120422 version?

Thanks!

Link to script: 
https://github.com/graysky2/profile-cleaner/blob/master/common/profile-cleaner