that would be pretty low for renewals
Given the 3 year gap between big feature releases, there's been a lot of noise about people not renewing until there's something to renew for. AFAIK the only full time devs are Kier and Chris, with a couple of folks on the side as some kind of contractor, not sure if full time or part time though. Also UK dev salaries are lower than US ones for sure.
As for IPS, the change to licensing is an interesting one - that if you are on the new terms, you *have* to renew every couple of years otherwise your licence is forfeit. I get the thinking from IPS on the subject - that otherwise someone could be happy on the version they're on, skip upgrades for 3 years, then renew to get the latest features without having invested in the dev cost in the interim, but I'm not *entirely* sold on the justification - plenty of other companies manage to do this just fine.
This is why with pay-to-keep software you *have* to give people a compelling reason to upgrade; this is why I pushed so hard for more features in SMF 2.1 because the same logic flies: people will hold out on what they have if it's good enough.
Which, to bring it back on topic, is even more interesting for ProBoards because it was clear that v5 *isn't* good enough for an increasing number of people, which means shelving v6 is a problem for them unless they're going to do a v5.5 - or just go to Fora (most likely)
That's one of the interesting things about the hosted space: as long as people have everything they need (and can get by otherwise), they'll happily play along. ProBoards users seem to expect more from the offering than the Jcink users, which I find deeply interesting given how much relatively-equal functionality there actually is there.