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January 2026 brought steady progress (15 PRs merged) on robustness and APIs: dependency and CI updates, wasm bindings and API improvements, protocol feature additions (AppData mechanisms and GREASE handling), better TreeSync error handling and PSK checks, plus work to store pending proposals. We also released two new versions of OpenMLS (technically in February on the 4th not in January). v0.7.2 This release includes critical security patches addressing vulnerabilities identified through external security research. We recommend all users update to the latest version immediately. ...

December with the holiday season was a quiet month for OpenMLS. Merged PRs December 2025 #1919: chore: update hpke-rs to 0.5.0 #1911: bump hpke to 0.4 #1910: fix: correction in tree operations KAT Contributors @raphaelrobert @franziskuskiefer

We merged 22 PRs in November. New Features and Fixes 🚀 We added a couple features from the MLS exntesions draft. OpenMLS now supports safe HPKE encrypt/decrypt with label, allowing applications to safely encrypt to public keys. It also supports the AppEphemeral proposal. The AppAck handling was updated in line with the extensions draft. Other parts of the supporting crates got updated to work with the features from the extensions draft. All features from the extensions draft are behind the extensions-draft-08 for now. ...

We merged 10 PRs in October. New Features and Fixes 🚀 This month saw a number of improvements and additions. New sqlx based storage provider: A new storage provider based on sqlx has been added, offering a another robust and feature-rich alternative for persistence (1854). Performance improvements: We’ve added a new from_components method to TreeNode to avoid unnecessary allocations, which should give a nice performance boost in tree operations (1864). PSK Validation: Pre-shared key validation has been improved, especially when processing Welcome messages (1862, 1863). API Re-addition: Make it easier to re-add clients that got forked (1855). Validation Fixes: We continue to improve our validation logic. This month we updated the validation for extension types in leaf node extensions (1831) and fixed references to the validation dashboard in some of our tests (1861). Contributors 🎉 We are also thrilled to welcome @WaterWhisperer as a new contributor. ...

We merged 15 PRs in September and released OpenMLSv0.7.1. v0.7.1 Release 🔐 The most critical update this month was the release of v0.7.1, which addresses a security vulnerability. We urge all users to upgrade to this version as soon as possible to ensure their applications remains secure. You can find more details about the vulnerability in the official security advisory: GHSA-qr9h-x63w-vqfm. New Features and Fixes 🚀 September and this release also saw the addition of some handy new features and important bug fixes: ...

We merged 8 PRs in August. Not bad for a summer month 🌞. We welcome @tbehner as a first time contributor, solving a long standing issue by adding the hmac function to OpenMlsCrypto trait. Thanks to @kkohbrok it is now also much easier to build external commits with the new external commit builder. let (mut dave_group, _bundle) = MlsGroup::external_commit_builder() .with_config(mls_group_config.clone()) .build_group(provider, verifiable_group_info, dave_credential) .unwrap() .load_psks(provider.storage()) .unwrap() .build( provider.rand(), provider.crypto(), &dave_signature_keys, |_| true, ) .unwrap() .finalize(provider) .expect("Error joining from external commit"); Merged PRs August 2025 #1829: Doc fixes #1828: disable large tree test #1825: adding the hmac function to OpenMlsCrypto #1824: make clippy happy #1823: Update README.md in sqlite storage #1822: chore: Add TryFrom for VerifiableCiphersuite #1814: Allow configuration of leaf node lifetime checks on join #1801: External commit builder Contributors @wysiwys @franziskuskiefer @tbehner @kkohbrok

We merged 16 PRs in July with fixes to documentation and code improvements, and most importantly, OpenMLS v0.7 got released 🎉. Important fixes that got merged in July are #1797, which ensures that the ratchet tree is trimmed correctly after processing proposals, and #1793, which corrects the calculation of the free index when inserting a new leaf node into the ratchet tree in certain cases. OpenMLS now also supports GroupContextExtensions in external proposals. ...

We merged 5 PRs in June with some small improvements. This was a quiet month, with the main focus on stabilization to prepare for the upcoming v0.7 release. Merged PRs June 2025 #1788: hpke: don’t use git dependency #1787: Update tls_codec to 0.4.2 #1786: fix: Tighten export functions API #1783: Update external proposal documentation with links to validation checks #1782: Add validation test for valn1504 Contributors @wysiwys @raphaelrobert @keks @franziskuskiefer

We merged 4 PRs in May with some significant improvements. #1774 introduced a flag in the commit builder, providing more granular control over group information creation. This enhancement allows for greater flexibility when managing MLS group states. We’ve improved error handling for old private messages in #1772. Now, when you encounter an outdated private message, OpenMLS will return a more specific error, making debugging and message management easier. And #1767 refines how updates are handled within OpenMLS by transitioning to the use of SignerBundle instead of Signer. ...

The openmls project continues to thrive not only because of the core team, but also thanks to the valuable contributions from our dedicated community. Last month saw 32 pull requests merged, all aimed at bolstering the stability and usability of the OpenMLS library. We added a usable, formally verified crypto backend with libcrux for use in OpenMLS. This is the first step towards making OpenMLS a high assurance library. We also welcome new contributors @Snazzah, who added support for external sender proposals #1750, as well as @timokoesters. ...