(CNN) — Twitter’s free blue “verified” checkmarks for notable users may finally be coming to an end.

Ever since Elon Musk took control of the company in October, he’s been threatening to remove the “legacy” checkmarks that confirmed the identities of users like government officials, corporations, journalists, celebrities and other high-profile tweeters.

Now Musk may follow through: “On April 1st, we will begin winding down our legacy verified program and removing legacy verified checkmarks,” the company wrote in a tweet Thursday.

A caveat, however: Twitter says this policy will go into effect starting on April Fool’s Day. Musk in particular has been known for April 1 trolling, including in 2018 when he falsely tweeted that his electric vehicle company Tesla had gone bankrupt.

“To keep your blue checkmark on Twitter, individuals can sign up for Twitter Blue,” the company’s tweet continued.

Twitter Blue is a subscription service that Musk relaunched late last year that costs individuals $84 a year or $8 a month. Charging fees provides a revenue stream for Twitter — and a needed one, as Twitter currently collects virtually all of its revenue from advertisers, who have been fleeing the social media platform since he took over.

The brief history of Twitter Blue

Charging for Twitter verification provides both additional revenue to Twitter and a way for Musk to show his disdain for government agencies, journalists and others. Yet building a replacement for the legacy verification program has proved to be fraught.

Twitter Blue first launched in the pre-Musk days of 2021, as a subscription service offering “power features” like undoing a tweet and saving bookmarks to folders. Musk relaunched the program in November 2022, including a blue checkmark in the features for paying users.

Immediately the program was flooded with users who paid for counterfeit accounts pretending to be users such as former President Donald Trump, Rudy Giuliani, LeBron James and Nintendo.

Before being suspended, the impostor Nintendo account tweeted an image of video game character Mario giving the viewer the middle finger. The LeBron James account falsely claimed the athlete had requested a trade. The fake Trump account tweeted, “This is why Elon Musk’s plan doesn’t work.”

Musk pulled the Twitter Blue program for a few weeks and relaunched it yet again in December, with additional steps for reviewing and approving subscribers. Beyond the checkmark, Blue also lets paying users edit a tweet up to 5 times within 30 minutes, create tweets up to 4,000 characters long and post HD videos.

The company also says Twitter Blue users will see 50% fewer ads in their home timelines, and that their tweets will be prioritized among replies, mentions and searches.

For companies and other organizations, Twitter Blue costs $1,000 a month for the main account and $50 a month for each additional related account.

— CNN’s Brian Fung contributed to this report.

Pay $84 a year for Twitter Blue or lose your checkmark beginning April 1, Twitter says