My opinion would be: If it's toolchain, support 5.8.1. Otherwise support 5.10.1 if reasonable, or 5.14.0 to be able to use keywords. 5.10.1 is by far the biggest user base due to RHEL6, but it's shrinking. There is a useful chart maintained of versions reported by cpanm, just remember it's a subsection of the community: http://cpanmetadb.plackperl.org/versions/ -Grinnz