What does your test involve/include? Other (mail related) Modules?

Reason I ask, is that mail headers use < and >. As memory serves, the relevant RFC probably mentions this. Point being; that unless Perl has processed your text prior to mail related Modules, or the SMTP(d) itself. This might be the problem.

Mind you, I'm going by memory on the RFC, and I don't know your test method.

The following may be pertinent RFC 6531, RFC 6152, (RFC 5248 interesting, but probably not relevant), RFC 2852

Just a thought

--Chris

#!/usr/bin/perl -Tw
use Perl::Always or die;
my $perl_version = (5.12.5);
print $perl_version;