Add a META.yml to the distribution. Your buildtool should be able to autogenerate it.
Make sure that the main module name and version are the same of the distribution.
Split the distribution, or fix the version numbers to make them consistent (use the highest version number to avoid version downgrade).
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 'use warnings' (or its equivalents) to all modules (this will require perl > 5.6), or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.
Error: HTML::FormatPS, HTML::FormatText, HTML::Formatter
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.