At work, we have:

• VMS machines that are running V5.8.6 because that's what shipped with the VMS version of Apache we are running. I have my own private copy of V5.16.2.
• Linux machines running various Red Hat releases. RH6.x machines have V5.10.1. RH7.x machines have 5.16.3. I have my own private copy of V5.24.1

At home I run gentoo which has V5.24.3.

Unfortunately, although I keep using perl for a lot of stuff I haven't really kept up with what changed in each release since around V5.10.