Meta has released Labyrinth 1.1, a major update to its encrypted storage protocol that dramatically improves the reliability of end-to-end encrypted backups on Messenger. The upgrade introduces a new sub-protocol that allows messages to be placed directly into a recipient's encrypted backup at the moment of sending, eliminating the previous dependency on the recipient's device being online.
“With Labyrinth 1.1, we’re making sure your messages are stored securely even if you lose your phone, switch devices, or go a long time without signing in,” a Meta spokesperson told reporters. “Each message is now wrapped with a unique encryption key and dropped directly into the backup – like a sealed envelope into a locked box that only the recipient can open.” No one — not even Meta — can read the contents.
Background
Labyrinth was first launched in 2023 as Meta’s protocol for end-to-end encrypting stored message history across devices on Messenger. The original version required a user’s device to come online before messages could be added to the encrypted backup, creating a window of vulnerability during device loss or extended offline periods.
Labyrinth 1.1 solves this by having senders encrypt and insert each message into the backup immediately. This ensures that even if the recipient never reconnects the lost device, the full history remains accessible after restoration. The updated protocol is already being rolled out broadly across Messenger, and Meta reports measurable improvements in backup success rates and restoration completeness.
What This Means
For ordinary users, the update means that losing a phone or switching to a new device no longer risks losing message history – nor does a long gap between sign-ins. The encrypted backup will contain messages from all conversations, even those sent while the user was offline.
The protocol’s design preserves end-to-end encryption: only the conversation participants hold the keys. This strengthens user privacy and aligns with Meta’s broader push toward default encryption across its apps. The updated white paper, “The Labyrinth Encrypted Message Storage Protocol,” provides full technical details and is available for download.
Read the full white paper: The Labyrinth Encrypted Message Storage Protocol.