Add a META.yml to the distribution. Your buildtool should be able to autogenerate it.
Add a section called "LICENSE" to the documentation, or add a file named LICENSE to the distribution.
Add =head1 LICENSE and the text of the license to the main module in your code.
Add a META.json to the distribution. Your buildtool should be able to autogenerate it.
Define the license if you are using in Build.PL. If you are using MakeMaker (Makefile.PL) you should upgrade to ExtUtils::MakeMaker version 6.31.
Add =head1 LICENSE and/or the proper text of the well-known license to the main module in your code.
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::SAX::Base, XML::SAX::Exception
Ask the owner of the distribution (the one who released it first, or the one who is designated in x_authority) to give you a (co-)maintainer's permission.
Split the distribution, or fix the version numbers to make them consistent (use the highest version number to avoid version downgrade).
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.