Zero metadata, group descriptions, native audio/video calls and more
Delta Chat and chatmail core teams have released version 2.48+, enhancing privacy with near-zero metadata transmission. The update includes full header protection, randomized dates, and encrypted group descriptions, while introducing native audio and video calling across platforms. These changes improve user privacy and functionality without relying on centralized infrastructure.
- ▪All meaningful message headers are now encrypted, with only minimal outer envelope data visible to transport servers.
- ▪The Date header is randomized within a 5-day window to prevent timestamp correlation attacks.
- ▪SecureJoin v3 encrypts initial chat setup messages and ensures backward and forward compatibility.
- ▪Native audio and video calls using WebRTC are now available on Android, iOS, and DeltaTouch with background support.
- ▪Group and broadcast channel descriptions are end-to-end encrypted and synchronized with membership changes.
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Zero metadata, group descriptions, native audio/video calls and much more! March 31, 2026 by Delta Chat and chatmail core release teams With the latest 2.48+ releases, a chat message reveals close to zero metadata to servers. For cryptographers and messenger enthusiasts, here are the key points on how we turned email very close to zero-metadata: No cleartext Auto-Submitted or threading headers. In addition to Subject, To, and group membership headers, we’re now also protecting Auto-Submitted, References, and In-Reply-To. This means that all meaningful header metadata now lives exclusively in the encrypted part of messages, implementing full Header Protection (RFC 9788). Transport servers only see a minimal so-called outer envelope. Randomized Date header.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at Delta.
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