Hi all,
With OS 6 we are changing the testing phase of the OS a bit: In the past pre-releases received a regular version number. From now on pre-releases will use the upcoming major/minor version, plus a release candidate designation, e.g. this first pre-release has the version number 6.0.rc1.
The 6.0.rc1 build is complete and available to download on the Operating System’s Github release page.
This new release comes with the latest Linux kernel 5.10 LTS on all platforms, the latest U-Boot release 2021.04, an updated build system Buildroot 2021.02. The integrated Docker Engine version is now 20.10.6.
Also new in this release is a component called “OS Agent”. It will improve the communication between the Supervisor and the Operating System. It will enable new features, such as enabling the data disk from the user interface. This is still work in progress, so stay tuned for updates in the future.
The user facing naming (e.g. file names) has been changed from hassos to haos. We also renamed the intel-nuc board to generic-x86-64 since the image is meant to support more than Intel NUC systems. Existing intel-nuc installations will get migrated to generic-x86-64.
The full list of changes is available on the Github release page.
Pascal and me have tested development releases as well as this release candidate on various platforms like ODROID-N2+ (Blue), Raspberry Pi 4 64-Bit, Intel NUC and Linux Virtual Machine Manager (KVM). My production instance runs OS 6 development releases since quite a while, so it is generally stable. But, before releasing OS 6 some testing by a larger audience is welcome!
You should feel somewhat comfortable around Home Assistant OS and in the terminal, just in case…
New installations as well as updates can be tested.
Important: If you decide to upgrade your active installation to 6.0.rc1, please take a snapshot and download it, just in case 
!
~ $ ha os info
<make sure you are on 5.13>
~ $ ha supervisor options --channel=beta
~ $ ha supervisor reload
~ $ ha os update
<this will update and reboot your system>
~ $ ha supervisor options --channel=stable
~ $ ha os info
<verify version has been updated>
You should now be running the latest OS 6.0.rc1 version.
It is safe to keep running your installation on 6.0.rc1. You will be able to update to the final release. In case you want to downgrade anyway, you can use this commands (make sure to switch to the stable channel first):
~ $ ha supervisor options --channel=stable
~ $ ha supervisor reload
~ $ ha os update --version=5.13
Note: OS 6 can only be downgraded to the lastest OS 5 release 5.13. However, from OS 5.13 it is should still be possible to downgrade to older releases.
Note 2: A downgrade of ageneric-x86-64 (OS 6) board to OS 5.13 using the console is not possible. This is due to the renaming of the board: OS release 5.13 uses intel-nuc. You can downgrade by using a USB flash drive: Store the hassos_intel-nuc-5.13.raucb on a USB flash drive with the file system name CONFIG. Use the “Import from USB” from the user interface, this should trigger the downgrade and a reboot. You can also re-install and restore the snapshot.
I am aware that several people have stability problems with later OS 5 releases on various setups. Unfortunately, so far I haven’t been able to reproduce or pinpoint this stability issues. Please test if you experience this problems also with release 6.0.rc1. If the problem is also reproducible with OS 6.0.rc1, please report in the respective issues (or create a new issue). I plan to invest more time trying to find the root cause of this issues.
Report bugs/regressions on the operating system issue tracker.
Update May 28th 2021:
Meanwhile we arrived at 6.0.rc3! With the latest Supvisor supervisor-2021.05.3 updating to it should work also on Intel NUC (the board type will automatically migrated to generic-x86-64, which is the new board supporting Intel NUC and other x86-64 machines).
Thanks & cheers,
Stefan
. I uploaded a renamed version for the update file so that the Supervisor is able to download the update file. Can you try again?