If you are using Build.PL define the {requires}{perl} = VERSION field. If you are using MakeMaker (Makefile.PL) you should upgrade ExtUtils::MakeMaker to 6.48 and use MIN_PERL_VERSION parameter. Perl::MinimumVersion can help you determine which version of Perl your module needs.

Add a META.json to the distribution. Your buildtool should be able to autogenerate it.

Add 'use warnings' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.

Error: XML::Liberal, XML::Liberal::LibXML, XML::Liberal::Remedy, XML::Liberal::Remedy::ControlCode, XML::Liberal::Remedy::EntityRef, XML::Liberal::Remedy::HTMLEntity, XML::Liberal::Remedy::InvalidEncoding, XML::Liberal::Remedy::LowAsciiChars, XML::Liberal::Remedy::NotUTF8, XML::Liberal::Remedy::StandaloneAttribute, XML::Liberal::Remedy::UndeclaredNS, XML::Liberal::Remedy::UnquotedAttribute, XML::Liberal::Remedy::XHTMLEmptyTag

Add all modules contained in this distribution to the META.yml field 'provides'. Module::Build or Dist::Zilla::Plugin::MetaProvides do this automatically for you.

Add a 'repository' resource to the META.yml via 'meta_add' accessor (for Module::Build) or META_ADD parameter (for ExtUtils::MakeMaker).

This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.