Twitter is rolling out a dramatic change to its timeline feature, four days after its CEO assured angry users that no such change was imminent.

In a blog post, Twitter announced they will be turning on a new feature for their users in the coming weeks. Instead of seeing tweets in reverse chronological order at the top of their feeds, users will see a selection of tweets chosen by an algorithm that matches tweets to users’ interests. This is precisely the sort of change that users were led to believe would not be introduced this week.

After a report in BuzzFeed last Friday claimed that Twitter planned to introduce the new Facebook-style timeline as a potentially mandatory alternative to its current real-time news feed, users revolted. They gathered on the #RIPTwitter hashtag, which quickly attracted over a million tweets from celebrities, commentators, and ordinary users.

In response to user protests, CEO Jack Dorsey made a series of tweets, appearing to promise that no change to users’ timelines would be introduced this week.

Hello Twitter! Regarding #RIPTwitter: I want you all to know we're always listening. We never planned to reorder timelines next week. — jack (@jack) February 6, 2016

It seems users were being lulled into a false sense of security. In their announcement, Twitter stressed that the change is optional. However, the change will be opt-out rather than opt-in: users will have the new timeline automatically switched on for them and will have to manually switch back to the old, chronological timeline via their user settings.

Users will also have concerns about how long the new timeline will remain optional. Facebook, a company whose success Twitter hopes to emulate, has a history of introducing optional changes before making them mandatory for all users.

Twitter’s change comes as the company’s stock price continues to tank. Shares in the company are currently trading at less than $15, down from over $25 in December. The company has also received increasingly negative media attention in recent weeks, facing accusations of political bias in the users it targets for punishment.

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