+
+ # for leafnode compatibility, we need to ensure Message-ID headers
+ # are only a single line. We can't subclass Email::Simple::Header
+ # and override _default_fold_at in here, either; since that won't
+ # affect messages already in the archive.
+ $hdr =~ s/^(Message-ID:)[ \t]*\r\n[ \t]+([^\r]+)\r\n/$1 $2\r\n/igsm;
+