Twitter faced a new wave of employees departures on Thursday, bringing fresh uncertainty about the social media platform’s future after its new owner Elon Musk ordered staff to commit to an “extremely hardcore” working culture or quit.

Dozens of employees have announced they were leaving the platform on the company’s internal Slack channels, according to two people familiar with the situation, ahead of a deadline Musk set requiring them to formally register their desire to be part of building “Twitter 2.0” or leave with three months severance pay.

Many shared emojis of a person saluting, or a blue heart, in a sign of camaraderie, one of the people said. Some users of Twitter, meanwhile, expressed concerns the latest exits could wreak havoc on the site.