Only one comment:
The body should be large, and you are passing to the function (using the stack) all the parameters.
I would pass it using references

Example:

outlook_mailer(\%mail);
[download]

In the sub, you obtain the parameters dereferencing the reference

my $mail_props = shift;
[download]

and then obtain the parameters with

$mail_props->{'to'}
[download]

See perldoc perlref for details

Hopes

$_=$,=q,\,@4O,,s,^$,$\,,s,s,^,b9,s,
$_^=q,$\^-]!,,print
[download]