Zephyr 4.4.0 Brings OpenRISC Support, Performance Gains, and Wi-Fi Direct Capabilities

The Zephyr Project has announced the 4.4 release of its eponymous real-time operating system (RTOS), the first under a new biannual release schedule — and which brings with it support for the OpenRISC architecture, Wi-Fi Direct support, expanded though still-experimental USB Host support, and more.

"On behalf of the Zephyr Project, I am thrilled to announce the general availability of Zephyr 4.4 — the first release under the project's new bi-yearly release cadence," says Zephyr's Benjamin Cabé of the new version. "Moving to two major releases per year gives the community more time to mature each release and makes it easier for downstream projects to plan upgrades (one release in April, one in October, like [Canonical's] Ubuntu!). This cycle brought contributions from over 930 individuals, delivering a release packed with significant networking improvements, support for a new processor architecture and much more."

Currently celebrating its tenth year, the Zephyr project offers a cross-vendor real-time operating system now compatible with over a thousand targets and counting — and the latest release, the first to ship with the Zephyr Software Development Kit (SDK) 1.0, continues its growing momentum. Among the new features is support for the 32-bit variant of the free and open source OpenRISC architecture, joining the earlier addition of RISC-V and proprietary architectures Arm, x86, Tenslica's Xtensa, ARC, MIPS, SPARC, and more.

Connectivity has also been upgraded, bringing support for Wi-Fi Direct peer-to-peer connections between compatible devices. There's also the inclusion of support for the popular WireGuard virtual private network (VPN) package, and an expansion to experimental support for acting as a USB Host for devices including video cameras. "This opens the door to embedded vision scenarios that pair really well with the networking additions," Cabé explains. "Once it becomes possible to connect virtually any webcam to a Zephyr-based device, it is easy to imagine building systems that capture a video feed and then expose or tunnel it over a direct peer-to-peer connection or a VPN link."

Other changes include the addition of one-time programmable (OPT) memory, biometrics, and wake-up controller device driver classes, performance gains for Arm Cortex-M-core devices, pressure-based CPU Frequency scaling for battery-powered devices needing bursty performance, a new "dashboard" build target providing an interactive HTML report, and a display driver for the QEMU emulator for the development of human-machine interface (HMI) projects away from actual hardware.

More information is available in the Zephyr 4.4.0 release notes, while those upgrading from previous releases are advised to read the migration guide first; source code is available on GitHub under the permissive Apache 2.0 license. For more on the project and how it has grown over the past decade, check out our interview with Cabé and Kate Stewart from Embedded World 2026.