Zephyr 4.0.0-rc1

Hello Zephyr developers!

The first release candidate for Zephyr 4.0.0 has been tagged:

https://github.com/zephyrproject-rtos/zephyr/releases/tag/v4.0.0-rc1

The merge window for features and enhancements is now closed for this release, and it will remain closed until 4.0.0 is released.

We are now in the stabilisation phase, and only bug-fix, documentation and stabilisation patches may be merged to the main branch. Additional features and enhancements, including new hardware support for the 4.0.0 release requires approval by the TSC.

You may continue to submit pull requests for new features to gather feedback early or collaborate with others, but the release team would like to encourage everyone to focus on testing, documentation improvements and fixing bugs.

We anticipate the coming weeks to be very busy reducing overall bug count. Please give this RC a test drive and report any issues on supported platforms (with a PR if possible).

Release milestone dates:
https://github.com/zephyrproject-rtos/zephyr/wiki/Release-Management

Release process:
https://docs.zephyrproject.org/latest/project/release_process.html

Regards,
The release team.