#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use XML::LibXML;

my $content = '<entry key="maxcompdatastripe" value="41943040" />';

my $entry = 'XML::LibXML'->load_xml(string => $content)->documentElement;
$entry->{value} = '20917520';
$entry->{merge} = 'keep';
say $entry;