Qubes OS 4.3.0-rc4 is available for testing

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We’re pleased to announce that the fourth release candidate (RC) for Qubes OS 4.3.0 is now available for testing. This minor release includes many new features and improvements over Qubes OS 4.2.

What’s new in Qubes 4.3?

  • Dom0 upgraded to Fedora 41 (#9402).
  • Xen upgraded to version 4.19 (#9420).
  • Default Fedora template upgraded to Fedora 42 (older versions not supported).
  • Default Debian template upgraded to Debian 13 (versions older than 12 not supported).
  • Default Whonix templates upgraded to Whonix 18 (upgraded from 17.4.3 in RC2; versions older than 18 no longer supported).
  • Preloaded disposables (#1512)
  • Device “self-identity oriented” assignment (a.k.a. New Devices API) (#9325)
  • Qubes Windows Tools reintroduced with improved features (#1861).

These are just a few highlights from the many changes included in this release. For a more comprehensive list of changes, see the Qubes OS 4.3 release notes.

When is the stable release?

That depends on the number of bugs discovered in this RC and their severity. As explained in our release schedule documentation, our usual process after issuing a new RC is to collect bug reports, triage the bugs, and fix them. If warranted, we then issue a new RC that includes the fixes and repeat the process. We continue this iterative procedure until we’re left with an RC that’s good enough to be declared the stable release. No one can predict, at the outset, how many iterations will be required (and hence how many RCs will be needed before a stable release), but we tend to get a clearer picture of this as testing progresses.

Barring any surprises uncovered by testing, we expect this fourth RC to be the final one, which means that we hope to declare this RC to be the stable 4.3.0 release at the conclusion of its testing period.

How to test Qubes 4.3.0-rc4

Thanks to those who tested earlier 4.3 RCs and reported bugs they encountered, 4.3.0-rc4 now includes fixes for several bugs that were present in those prior RCs!

If you’d like to help us test this RC, you can upgrade to Qubes 4.3.0-rc4 with either a clean installation or an in-place upgrade from Qubes 4.2. (Note for in-place upgrade testers: qubes-dist-upgrade now requires --releasever=4.3 and may require --enable-current-testing for testing releases like this RC.) As always, we strongly recommend making a full backup beforehand and updating Qubes OS immediately afterward in order to apply all available bug fixes.

If you’re currently using an earlier 4.3 RC and wish to update to 4.3.0-rc4, please update normally with current-testing enabled. If you use Whonix, please also upgrade from Whonix 17 to 18, if you have not already done so.

Please help us improve the eventual stable release by reporting any bugs you encounter. If you’re an experienced user, we encourage you to join the testing team.

Known issues in Qubes OS 4.3.0-rc4

It is possible that templates restored in 4.3.0-rc4 from a pre-4.3 backup may continue to target their original Qubes OS release repos. This does not affect fresh templates on a clean 4.3.0-rc4 installation. For more information, see issue #8701.

View the full list of known bugs affecting Qubes 4.3 in our issue tracker.

What’s a release candidate?

A release candidate (RC) is a software build that has the potential to become a stable release, unless significant bugs are discovered in testing. RCs are intended for more advanced (or adventurous!) users who are comfortable testing early versions of software that are potentially buggier than stable releases. You can read more about Qubes OS supported releases and the version scheme in our documentation.

What’s a minor release?

The Qubes OS Project uses the semantic versioning standard. Version numbers are written as [major].[minor].[patch]. Hence, releases that increment the second value are known as “minor releases.” Minor releases generally include new features, improvements, and bug fixes that are backward-compatible with earlier versions of the same major release. See our supported releases for a comprehensive list of major and minor releases and our version scheme documentation for more information about how Qubes OS releases are versioned.

This is a companion discussion topic for the original entry at https://www.qubes-os.org/news/2025/12/06/qubes-os-4-3-0-rc4-available-for-testing/
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Continuing the discussion from Qubes OS 4.3.0-rc4 is available for testing:

Thanks,appreciated !!!

Upgraded on DELL Precision 5550.
All good so far.

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Is this the expected / preferred way to report a successful installation or upgrade for a RC ?

I read the info on ‘How to test Qubes 4.3.0-rc4’ in the initial announcement - but - it addresses only the case, where issues / problems occur …

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Not sure,help me to understand the corect approved way to do it, so i can avoid any further derails from the official written rules and conditions,i feel obliged to apologise to you, sorry !!

Thanks for the reminder, it will not happen again, me,saying anything about the truly enjoyment of having the upgrade completed succesfully.
Instead…i will apply reverse logic,as you demanded and report back to our brave developers team only pain,suffering and troubles… :wink:

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@newUser2025: Sorry for making my intent not clearer !

I just wanted to ask the team, what they would prefer for a new system I successfully installed myself …

I simply don’t know.

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Reporting successful installations here is fine. :slight_smile:

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Installation on a Lenovo ThinkPad E14 (i5 w/ 16GB) went fine w/o any issues. Will send an HCL entry separately.

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Clean install upgraded to QubesOS 4.3-rc4. During the install, I had a
worrying error from QubesOS installer that it had “failed to set new efi
boot target,” and that “the system wouldn’t be bootable”. I chose the
option to ignore the error and keep installing. After the first reboot,
it correctly booted into the second phase of installation. I think the
error message was due to the fact that my “efi” (or bootloader, I guess)
already had a boot entry named “QubesOS” and that the new install also
wanted to create a new entry with that same name.

After this, installation went fine. I restored my 550 GB encrypted
backups from QubesOS 4.2.4 without a problem.

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Same over here. Full backup (with templates). SSD format, fresh installation on a NV41 without a single hiccup. Tested three different configs (with/without templates, varying USB security/trust options etc.): Everything works just fine. Went with plain defaults in the end.

Restoring backups was easy as cake. Couldn’t reuse my old fedora-42-templates for service qubes though, but my installation is rather frugal. Reused the old dnf history list outputs to rebuild my templates. My custom (minimal) templates on the other hand (mostly debian-13 based for printing, scanning, messengers, network backups etc.) worked out of the box as they did with 4.2.4.

Preloaded disposables save some seconds, when viewing documents.

The qrexec-thinning adds to a more “snappy/fluent” UX.

New and much more intuitive USB widget/menu, a way better qubes-restart function for qubes-update-gui.

A decent default theme with flat icons and a much more streamlined experience, when attaching the laptop to my desktop screen with KVM: switching resolutions meant losing some windows when position wasn’t optimal before. It works now as advertised: a single USB-C gives pd, alt displayport, keyboard, mouse and ethernet within 2secs. No flickering, no black screens, no “lost” windows.

But what’s really nice is the “boost”, LibreOffice got with the default gtk3 interface. I used to start it up with an alias on 4.2.4 for starting with gtk4, that significantly sped things up when scrolling large documents, but brought some color/icon inconsistencies to the table. Maybe the older fedora builts were b0rked? Anyway, the alternative appstart is retired, gtk3 standard now works for me.

Even though it seems like a tiny step from 4.2 to 4.3, because so many smaller things evolve continously and/or are backported, it’s a huge improvement for me in total.

The only thing I didn’t test so far was switching from split-gpg to split-gpg2. Maybe over the holidays.

A big “many thanks” to the qubes-os-team!

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