...
my $mm = $mail->GetNamespace("MAPI");
my $Folder = $mm->Folders("Personal Folders");
my $client_folder = $Folder->Folders("qa1");
my $Item = $client_folder->Items;
my $last_email = $Item->GetLast();
if ($last_email->{Class} eq olMail) {
         print $last_email->{To};
}
...