From my point of view, situations like this call for an emergency email or front end push message to ALL admins. I installed the update on 5 sites and had no idea it had effectively deactivated sign-ups on all of them. (I don’t use quick-registration) And this includes sites with like 100 new members a day (and potential clients which might never come back). If I hadn’t seen this topic, the problem might have persisted for days, if not weeks. There isn’t even a backend warning. Having the main registration form working isn’t “optional” as the grey “optional update” link suggest, it’s absolutely CRUCIAL.