Every character you have that logs in with the addon active is added to a list, and that list is then broadcast every time you log in, on any character running the addon, to generate the list of alts that shows up when you mouseover someone's name in chat.
Because of that, by default the addon is disabled on all your characters when it's first installed, so you can choose which ones are added to the list. Just check that you have it enabled.
I haven't bothered updating it because it still works fine, and the only thing that has changed is the version number for WoW, which isn't worth making thousands of people do another download for so the number in the addon matches.
I might do a proper update for the next expansion, if I end up playing it, otherwise I'll just make changes to keep F2PAddon working.