My guess would be a change in either the Perl version or the XML::Parser version. If the change in behaviour come from the Perl version then you can probably re-install the old version as perl5-xxx and use it for this CGI. If it is an XML::Parser problem then maybe Potato used XML::Parser 2.27 and Woody upgraded to XML::Parser 2.30, which has a problem with marking strings as UTF-8 (actually not marking them properly, I believe). You could re-install the old version, it is still on CPAN. You can also check the version of CGI.pm but I don't think it should impact, it is pretty good at keeping backward compatibility.