I'm translating a document from a business meeting into English .
Participants are often being implored to finish their tasks by November, as planned, and in no way to December.
I'll give some more background to focus my question a bit: this is a company project, and the management has set deadlines that all of the participants are supposed to meet. There may be all kinds of reasons that might prevent them from finishing their tasks by those deadlines, but the management is emphasizing that December would be catastrophic, and is imploring them to do whatever they can so as not to get into that situation.
I need a word or phrase to replace "going past a deadline".