WhatsApp cofounder Jan Koum, currently a member of Facebook’s board of directors, is preparing to leave the company. Koum confirmed his plans to leave in a Facebook post, less than an hour after the Washington Post reported that he was planning on leaving.

“I’m leaving at a time when people are using WhatsApp in more ways than I could have imagined. The team is stronger than ever and it’ll continue to do amazing things,” Koum wrote. “I’m taking some time off to do things I enjoy outside of technology, such as collecting rare air-cooled Porsches, working on my cars and playing ultimate frisbee.” Koum did not say when his departure date would be.

WhatsApp currently has roughly 1.5 billion monthly active users. Koum cofounded the company with Brian Acton in 2009. Acton and Koum sold the company to Facebook in 2014, at which point it had roughly 500 million users. Facebook acquired WhatsApp for more than $16 billion.

Acton left Facebook in September. In mid-March, he urged users to delete Facebook in wake of the news that Facebook had suspended data analytics firm Cambridge Analytica, employed by President Donald Trump’s campaign during the 2016 presidential election. British news outlet The Guardian reported that Cambridge Analytica improperly obtained the personal data of more than 50 million Facebook users and used it to create “psychological profiles” of U.S. voters. The number of affected users was later revised to up to 87 million by Facebook.

Since Facebook acquired WhatsApp, it has made changes to the app that are antithetical to Koum and Acton’s original vision. The original WhatsApp had a 99 cents per year subscription, which Facebook scrapped after the acquisition. The founders pledged when announcing the acquisition that “WhatsApp will remain autonomous and operate independently” — but that changed in 2016 when WhatsApp agreed to share a limited amount of WhatsApp user data, including phone numbers, with Facebook.

Koum and Acton also called online advertising — which is a central component of Facebook’s business model  — a “disruption to aesthetics, an insult to your intelligence, and the interruption of your train of thought.” Facebook generated nearly $11.8 billion in revenue from advertising during the first quarter of 2018.

The Post reported that Koum was ultimately “worn down by the differences in [his and Facebook’s] approach.”

News of Koum’s departure comes just a day before Facebook’s annual F8 conference for developers, where the company is likely to reveal more plans to monetize its messaging apps like WhatsApp. In January, Facebook launched WhatsApp Business, a separate version of the WhatsApp chat app for businesses. The company said on its most recent earnings call that WhatsApp Business now has more than 3 million users.