Elon Musk reportedly fired several dozen Twitter employees the night before Thanksgiving, most of whom were engineers—axing them despite them opting into CEO Elon Musk’s “Twitter 2.0,” which promised a “hardcore” workplace. The firings, first reported by The Verge, will include a severance package of four-weeks pay to those let go. It’s unknown how many engineers were fired, but the email indicated it was because their code was “not satisfactory.” The firings came as a surprise inside Twitter, sources at the company told Business Insider.

For the engineers who remain at Twitter, which has been bleeding employees since Musk’s takeover in October, the email laid out stricter guidelines of them moving forward, which will include them emailing “code samples” weekly for inspection. The Verge reported that some engineers received a warning email about their performance, signaling that they’d be next to go if they don't improve.