Two high-ranking Facebook execs — chief product officer Chris Cox and Chris Daniels, who has run the WhatsApp messaging product — are leaving the company.

CEO Mark Zuckerberg announced the changes in a memo to employees, which Facebook shared in its news blog.

The departures come after Zuckerberg last week outlined a new privacy vision for Facebook, setting plans for private communications on the company’s apps to be fully encrypted — and for user content and messages to self-destruct after a certain period of time.

Cox (pictured above) joined Facebook in 2005 as a software engineer and helped build the first versions of key Facebook features, including News Feed. In 2008 he became Facebook’s first VP of product, where he built the initial product management and design teams, before being promoted to chief product officer in 2014 where he has overseen all of the company’s apps: Facebook, Instagram, WhatsApp and Messenger.

“For a few years, Chris has been discussing with me his desire to do something else,” Zuckerberg wrote in the memo. “At this point, we have made real progress on many issues and we have a clear plan for our apps, centered around making private messaging, stories and groups the foundation of the experience, including enabling encryption and interoperability across our services. As we embark on this next major chapter, Chris has decided now is the time to step back from leading these teams.”

In a farewell note Cox posted on Facebook, he said in part that the company’s shift to “a modern communications platform that balances expression, safety, security, and privacy” will be “a big project and we will need leaders who are excited to see the new direction through.”

In what is likely pure coincidence, Facebook’s products suffered record outages and access problems for many users across its suite of apps, including Facebook and Instagram, over a 24-hour period starting Wednesday around noon ET.

Zuckerberg said he doesn’t plan to immediately tap a replacement for Cox. Instead, the heads of each of the products (Facebook, Instagram, Messenger and WhatsApp) report directly to Zuckerberg.

Facebook’s apps strategy has been led jointly by Cox and Javier Olivan, VP of growth, who has been responsible for all of the central product services that work across apps, including safety and integrity, analytics, growth, and ads. Olivan will take on a new role to identify “where our apps should be more integrated,” according to Zuckerberg.

With Daniels also exiting the company — less than a year after Zuckerberg moved the former business development exec from running Facebook’s Internet.org initiative — the new head of WhatsApp is Will Cathcart, who previously has been in charge of running the Facebook app.

According to Zuckerberg, Cathcart “led our shift to focusing on meaningful social interactions and has significantly improved the performance and reliability of the app.” In addition, the CEO noted, Cathcart “believes deeply in providing end-to-end encryption to everyone in the world across our services.”

In addition, Fidji Simo, previously head of video for Facebook, will be the new head of the Facebook app to take over for Cathcart. Simo, who joined the company in 2011 from eBay, had been in charge of video, games and monetization at Facebook, managing a team of more than 600 product managers and engineers.

Facebook hasn’t announced a new head of video to replace Simo. “She has played key roles in building many aspects of the Facebook app, including leading our work on video and advertising,” Zuckerberg wrote. He added that Simo has already led the team for much of 2018 while Cathcart was out on parental leave, and “she is the clear person to lead these efforts going forward.”

“While it is sad to lose such great people, this also creates opportunities for more great leaders who are energized about the path ahead to take on new and bigger roles,” Zuckerberg wrote.

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