This will work, assuming your version numbers and subnumbers don't exceed 1000. This is of course the famous Shwartzian Transform.

#!/usr/local/bin/perl

use strict;

my @versions=qw(2.0.0 1.0.9 1.0.10 1.1.0 1.1.2);

my @sversions = 
       map {$_->[0]} 
         sort {$a->[1] <=> $b->[1]} 
           map {
            my ($a1,$a2,$a3) = split(/\./,$_);
            [$_,$a1*1000000 + $a2*1000 + $a3]
           } @versions;
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-pete
"I am Jack's utter lack of disbelief"