Meta is rolling out end-to-end encryption for one-on-one chats and calls on Messenger, finally fulfilling a promise that’s been in the works for quite awhile. When end-to-end encryption is on, only you and the person you send a message to in Messenger can see its contents, the company claims.

Encrypted chats were first introduced as an opt-in feature in Messenger in 2016, but after a long windup, end-to-end encrypted messages and calls for conversations between two people will now be the standard going forward.

“This has taken years to deliver because we’ve taken our time to get this right,” Loredana Crisan, VP of Messenger, said in a statement shared with The Verge. “Our engineers, cryptographers, designers, policy experts and product managers have worked tirelessly to rebuild Messenger features from the ground up.”

According to Crisan, you won’t sacrifice Messenger features when using encrypted chats, so you’ll still be able to use things like themes and custom reactions. However, Crisan notes that it may “take some time” for all Messenger chats to switch over to default encryption.

While this is a good step, end-to-end encryption for group Messenger chats is still opt-in for now. Instagram messages are also not encrypted by default, though Meta said in August that would happen “shortly after” the rollout of default private Messenger chats.

CEO Mark Zuckerberg announced in 2019 that the company planned to move toward encrypted ephemeral messages across its messaging apps. “I believe the future of communication will increasingly shift to private, encrypted services where people can be confident what they say to each other stays secure and their messages and content won’t stick around forever,” he wrote in a Facebook post. “This is the future I hope we will help bring about.”

Enabling encryption by default will mean that Meta should not only be unable to see the contents of most Messenger chats, but that it also won’t be able to hand them over to law enforcement. Last year, the company drew headlines when a 17-year-old from Nebraska and her mother faced criminal charges for performing an illegal abortion after police obtained their Messenger chat history. Anti-encryption advocates say that the technology makes it harder to find bad actors on messaging apps like WhatsApp, which is already encrypted by default.