The task of sorting just any version numbers is not well defined, because everybody does this differently. Examples: Perl v5.20 is the same as Perl 5.020. If you sort the two versions numbers "2.5" and "2.5_rc1" with Perl's sort, then "2.5" will sort before "2.5_rc1". More generally: Is 5.02 the same as 5.020, or even the same as 5.2? Does 0.5 come before or after 0.1, before or after 0.10, and before or after 0.5.x? The list goes on.

The problem for me is not as much in finding the answers, but learning to ask the right questions.....

Then may I suggest the question to be "How do I sort Debian version numbers?"

This question will bring you to the Debian Policy Manual, which defines quite well how such version numbers are to be compared, as well as Debian::Dpkg::Version.