One of the last major firewalls standing between Facebook’s family of apps is no more: Starting today, Instagram users can message people on Facebook, and vice versa. How? Messenger, the Facebook-owned messaging app, has slid into Instagram’s DMs. An update replaces direct messages on Instagram with Messenger, which will be embedded inside the app. No need to download the Messenger app separately, as the Facebook app still requires; no need to link your Facebook account, or even have a Facebook account at all.

The update is a significant step toward a vision laid out by Mark Zuckerberg last year of knitting together the messaging systems on Facebook, Instagram, and WhatsApp, which between them have over 2.6 billion users. “We want to give people a choice so they can reach their friends across these networks from whichever app they prefer,” the CEO wrote at the time. In addition to convenience, he touted the security and privacy advantages—namely, end-to-end encryption, which has been the default on WhatsApp since 2016.

End-to-end encryption is also part of what makes merging the platforms so tricky. Facebook engineers told WIRED earlier this year that making encryption the default on Messenger will take years—and so, by extension, will a full integration of all three apps.

Adam Mosseri, the head of Instagram, confirmed that full end-to-end encryption remains on the company’s map, but did not say when it will get there. Wednesday’s update introduces some other privacy features in the meantime. A new “Vanish mode” for both Instagram and Messenger lets you make messages disappear, modeled after ephemeral messaging platforms like Snapchat. On Messenger, messages sent in Vanish mode will also by default be end-to-end encrypted, building off an existing feature on the app called Secret conversations. On Instagram, the Vanish mode messages are encrypted in transit, but not end-to-end, which means that Facebook or an interloper could hypothetically grab them off of the company’s servers; Instagram says it will retain these messages for reporting purposes. So although the mode is available on both Messenger and Instagram, you cannot send vanishing messages from one network to the other.

There are at least a few new features designed to keep Instagram and Facebook friends separate: You can choose not to receive messages from people on Facebook, for example, and can choose not to link the accounts at all. Nor does the update combine inboxes—messages on Instagram will remain in the Instagram app, while messages on the stand-alone Messenger app will stay there. Threads, Instagram’s stand-alone messaging app for close friends and family, remains unchanged.

Facebook, for its part, sees this consolidation as a way to maintain standards across all of its platforms. Its work on “integrity,” which involves managing the risk of election interference and misinformation, will carry over from Facebook’s Messenger to the new Messenger on Instagram. Message forwarding, one of the new updates on Instagram, will have the same limits that Facebook introduced for Messenger earlier this month. And the same tools to report suspicious activity or block unwanted messages will now be available on both apps.