# Fedora CoreOS rebasing to Fedora Linux 41
Fedora Linux 41 was released today [[1]]. The Fedora CoreOS `testing` stream has been rebased and is currently rolling out. In two weeks, it will be promoted to the `stable` stream.
For more information about Fedora 41, see the Fedora Project’s list of official Changes [[2]] and the Fedora CoreOS analysis of each Change [[3]].
The following changes require special attention:
- Fedora CoreOS is dropping Wi-Fi firmware packages that were split into subpackages of linux-firmware [[4]]. If you are currently using Wi-Fi, see the documentation for how to keep it enabled [[5]].
- Composefs is now enabled by default [[6]]. Pay special attention to the known issues [[7]].
- In systemd v256 cgroups v1 support was disabled. If you’ve opted out of the cgroups v2 migration in the past, your system will fail to boot after upgrading.
- moby-engine/Docker was updated in Fedora from version 24 to version 27. Please see the notes [[8]] with each release of moby and also the deprecated/removed features page [[9]] to see if there is any noteworthy changes for your use cases.
Please test out the `testing` stream and report any issues in our issue tracker [[10]].
Thank you to everyone helping find issues by running the `next` and `testing` streams!
The Fedora CoreOS Team
[1]: https://fedoramagazine.org/announcing-fedora-linux-41/
[2]: https://fedoraproject.org/wiki/Releases/41/ChangeSet
[3]: https://github.com/coreos/fedora-coreos-tracker/issues/1714
[4]: https://github.com/coreos/fedora-coreos-tracker/issues/1575
[5]: https://docs.fedoraproject.org/en-US/fedora-coreos/sysconfig-enabling-wifi/
[6]: https://docs.fedoraproject.org/en-US/fedora-coreos/composefs/
[7]: https://docs.fedoraproject.org/en-US/fedora-coreos/composefs/#_known_issues
[8]: https://github.com/moby/moby/releases
[9]: https://github.com/docker/cli/blob/master/docs/deprecated.md
[10]: https://github.com/coreos/fedora-coreos-tracker/issues?q=sort%3Aupdated-desc+is%3Aissue+is%3Aopen
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---
# Fedora CoreOS rebasing to Fedora Linux 40
Fedora Linux 40 was released today[[1]]. The Fedora CoreOS `testing` stream has been rebased and is currently rolling out. In two weeks, it will be promoted to the `stable` stream.
For more information about Fedora 40, see the Fedora Project’s list of official Changes[[2]] and the Fedora CoreOS analysis of each Change[[3]].
The following changes require special attention:
- Podman v5.0[[4]]: This release contains breaking changes. See the Podman website[[5]] and the tracker issue[[6]] for details.
- Assign individual, stable MAC addresses for Wi-Fi connections[[7]]: If you are using Wi-Fi, then your system's MAC address will likely change after the update.
Please test out the `testing` stream and report any issues in our issue tracker[[8]].
Thank you to everyone helping find issues by running the `next` and `testing` streams!
The Fedora CoreOS Team
[1]: https://fedoramagazine.org/announcing-fedora-linux-40/
[2]: https://fedoraproject.org/wiki/Releases/40/ChangeSet
[3]: https://github.com/coreos/fedora-coreos-tracker/issues/1626
[4]: https://fedoraproject.org/wiki/Changes/Podman5
[5]: https://blog.podman.io/2024/03/podman-5-0-breaking-changes-in-detail/
[6]: https://github.com/coreos/fedora-coreos-tracker/issues/1629
[7]: https://fedoraproject.org/wiki/Changes/StableSSIDMACAddress
[8]: https://github.com/coreos/fedora-coreos-tracker
---
[4](https://discussion.fedoraproject.org/t/fedora-coreos-next-stream-rebased-to-fedora-linux-40/109729)
https://discussion.fedoraproject.org/t/fedora-coreos-rebasing-to-fedora-linux-39/95330
---
- https://github.com/coreos/fedora-coreos-tracker/issues/1655
- https://github.com/coreos/fedora-coreos-tracker/labels/F40-Changes
The Fedora Linux 40 Beta was released today[[1]] and our Fedora CoreOS `next` stream has been migrated to Fedora Linux 40 content. Existing nodes on the `next` stream will update as normal over the following days.
The Fedora Project accepted changes for Fedora 40 are in the Wiki[[2]] and the Fedora CoreOS analysis of each change is documented in the tracker[[3]].
The following changes require special attention:
- Podman v5.0
- https://fedoraproject.org/wiki/Changes/Podman5
- https://github.com/coreos/fedora-coreos-tracker/issues/1629
The following changes may impact some specific setups:
- Switch to using OSBuild for most CoreOS boot image building
- Newly deployed `qemu` or bare `metal` systems will use disk images built using OSBuild.
- https://github.com/coreos/fedora-coreos-tracker/issues/1653
- Enable IPv4 Address Conflict Detection by default
- Conflict detection can delay startup by ~200ms.
- https://fedoraproject.org/wiki/Changes/Enable_IPv4_Address_Conflict_Detection
- https://github.com/coreos/fedora-coreos-tracker/issues/1656
- Assign individual, stable MAC addresses for Wi-Fi connections
- If you are using WiFi, then your systems MAC address will likely change after the update.
- https://fedoraproject.org/wiki/Changes/StableSSIDMACAddress
- Switch pam_userdb from BerkeleyDB to GDBM
- If you have overlayed vsftpd on your systems and use pam_userdb, then you need to convert the database using the instructions from [pam_userdb](https://docs.fedoraproject.org/en-US/fedora/rawhide/system-administrators-guide/pam_userdb/).
- https://fedoraproject.org/wiki/Changes/PamBerkeleyDBtoGdbm
- https://github.com/coreos/fedora-coreos-tracker/issues/1634
Please test out the `next` stream over the coming weeks and report any issues in our issue tracker[[4]].
Thank you to everyone helping find issues by running the next stream!
The Fedora CoreOS Team
[1]: https://fedoramagazine.org/announcing-fedora-linux-40-beta/
[2]: https://fedoraproject.org/wiki/Releases/40/ChangeSet
[3]: https://github.com/coreos/fedora-coreos-tracker/issues/1626
[4]: https://github.com/coreos/fedora-coreos-tracker