Hi everyone,

We are pleased to announce the release of Zephyr RTOS version 2.4.0!

Major enhancements with this release include:

• Introduced initial support for virtual memory management.
• Added Bluetooth host support for periodic advertisement and isochronous channels.
• Enabled the new TCP stack, TCP2, by default. This stack was introduced in Zephyr v2.1.0 to improve network protocol testability with open source tools.
• Introduced a new toolchain abstraction with initial implementations for GCC and LLVM/Clang, and groundwork for future support of commercial toolchains.
• Moved to using C99 integer types and deprecate Zephyr integer types. The Zephyr types can be enabled by Kconfig DEPRECATED_ZEPHYR_INT_TYPES option.

During this release cycle we also:

• Migrated to a new CI infrastructure.
• Started aggregating board farm test results from multiple companies.
• Agreed on a set of MISRA-based coding guidelines and a plan to implement them.
• Reduced a large backlog of low priority bugs.

The detailed release notes can be found here:

https://github.com/zephyrproject-rtos/zephyr/releases/tag/zephyr-v2.4.0

The next release, v2.5.0, is scheduled for January 29^th, 2021. We’ll select a release manager in the next few days. The merge window is now open!

Thank you to everyone that contributed features, documentation, testing, infrastructure, and bug fixes!

Maureen