//Info/Other[Type/text()="LN"]/Id

##</code><code>##

use strict;
use warnings;

use XML::LibXML qw( );

my $root = XML::LibXML->new->parse_fh(*DATA)->documentElement();
for my $node ( $root->findnodes(
   '//Info/Other[Type/text()="LN"]/Id'
) ) {
   print($node->textContent(), "\n");
}

__DATA__
<?xml version="1.0" encoding="ISO-8859-1"?>
<OPEN>
...
</OPEN>

##</code><code>##

WXY12345678
12345678XZW