"use UNIVERSAL" is a fatal error since perl 5.22 cf. http://perldoc.perl.org/perldelta.html#use-UNIVERSAL-%27...%27-is-now-a-fatal-error plus https://code.google.com/p/maildirsync/source/diff?spec=svn8060548654ea5f82ac45d1c15b0aeaebe97455a5&r=8060548654ea5f82ac45d1c15b0aeaebe97455a5&format=unidiff&path=/maildirsync.pl https://bugs.debian.org/809818