It has happened that a number of missions had to be rescheduled - and nothing wrong with that, as players are often busy or otherwise preoccupied.
However we'd like to avoid a situation where players wait for a mission with assumption it takes place, only for it to be cancelled/postponed due to lack of interest. Because of that, as of now we are introducing a rule:
Unless stated otherwise, a mission will take place only if it has at least 4 signups. Otherwise you can assume it to be postponed automatically.
If you as a player wish to participate in a mission but aren't 100% sure if you will be able to appear on it, feel free to sign up tentatively. It will count towards the 4 signups requirement and there aren't any consequences for signing up and then not showing up (whether you signed up tentatively or not).