In addition to the CSA’s official Software Development Kit, matter.js now implements the specifications of Matter 1.6.1. The alternative SDK, developed under the umbrella of the Open Home Foundation, has been released in an updated version. Matter.js 0.18.0 (link) introduces a new controller API and is “the most specification-compliant” version of the JavaScript tool to date, according to lead developer Ingo Fischer on LinkedIn (link).
Among the new features is full support for Matter 1.6.1, covering all software clusters and data types. Group communication (Groupcast), in particular, has been overhauled and is now enabled by default. matter.js is also designed to automatically analyze each device endpoint and check for the presence of required clusters and mandatory elements, a feature that should make developers’ day-to-day work easier.
Since the software also forms the core of the Open Home Foundation’s Matter Server, the new features are expected to make their way into Home Assistant soon. A beta version of the server with Matter 1.6.1 support has already been released (link).
What is Matter 1.6.1?
The latest version of the Matter specifications was published by the Connectivity Standards Alliance (CSA) in September 2026 with little fanfare. The minor maintenance update is the third extension of the standard this year, following Matter 1.5.1 in March and Matter 1.6 in June.
Matter 1.6.1 does not include any new device types but focuses on optimizing existing features. For example, the Groupcast cluster introduced in version 1.6 has been revised. It allows devices to send a single message to a group rather than addressing each recipient individually, an advantage when controlling multiple lights simultaneously, among other applications. The new cluster consolidates functions that were previously distributed across several locations and introduces the use of a multicast address that can be shared by all groups.
In addition, the “Chime” device type has been updated. It can now play preinstalled sounds, such as a gong, which benefits audio and video doorbells. Access control has been optimized, and the camera cluster includes further refinements designed to make video streaming more stable and optimize clip recording.
As with every new Matter release, the specifications must be supported by both the end device and the platform being used. It may therefore take months, if not years, before the new features see widespread adoption.
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