The key word being important. After releasing fetchware to CPAN, I got back CPAN Testers reports that had hundreds of given/when deprecation warnings. These warnings would just be completely insane when actually running the program on newer Perls, so given/when had to go byebye.

I used vim's cool but ancient s/// command to find and replace the givens and whens with their appropriate ifs. Unfortunately, I goofed up so profoundly that before bugs were reported to github, I had absolutely no idea that fetchware's command line interface was completely broken.