Qubes OS 4.3.1-rc1 is available for testing

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The first release candidate (RC) for Qubes OS 4.3.1 is now available for testing. This patch release aims to consolidate all the security patches, bug fixes, and other updates that have occurred since the release of Qubes 4.3.0.

What’s new in Qubes 4.3.1?

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 with certainty, 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.

Since the changes between 4.3.0 and 4.3.1 are relatively minor, we currently don’t anticipate any major problems requiring a second RC. We currently expect to be able to publish the stable 4.3.1 release in one to two weeks.

How to test Qubes 4.3.1-rc1

If you’d like to help us test this RC, the best way to do so is by performing a clean installation with the new ISO. As always, we strongly recommend making a full backup beforehand and updating Qubes OS immediately afterward in order to apply all available bug fixes.

As an alternative to a clean installation, there’s also the option of performing an in-place upgrade without reinstalling. However, since Qubes 4.3.1 is a patch release, it’s essentially Qubes 4.3.0 inclusive of all updates to date, which largely amounts to just using a fully-updated 4.3.0 installation. By contrast, a clean installation covers other areas that could also benefit from testing, such as the installation procedure, which is why it’s the recommended testing method.

Regardless of your testing method, 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 4.3.1

It is possible that templates restored in 4.3.1 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 4.3.1 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 patch release?

The Qubes OS Project uses the semantic versioning standard. Version numbers are written as [major].[minor].[patch]. Hence, we refer to releases that increment the third number as “patch releases.” A patch release does not designate a separate, new major or minor release of Qubes OS. Rather, it designates its respective major or minor release (in this case, 4.3) inclusive of all updates up to a certain point. 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/2026/05/28/qubes-os-4-3-1-rc1-available-for-testing/
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I think it would be super-good to have a link to a list of the :

…or at least to the highlights.

I shall be going to look for a few things - little and big - in the issues db, but maybe there are others that I might watch for.

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Thanks for the feedback. Here’s a link to a filtered list of all issues that meet the following criteria:

  • Bug affecting 4.3
  • Closed as completed between 2025-12-21 (the release date of 4.3.0) and 2026-05-28 (the date of this announcement)
  • Was not closed as “cannot reproduce,” “declined,” “duplicate,” “not applicable,” “self-closed,” or “upstream issue”
  • Does not pertain to the website, infrastructure, or tests

However, this list still has some limitations:

  • It doesn’t exclude documentation issues, because sometimes an issue is about fixing something in the code and in the documentation, and we don’t want to exclude those. However, this means the list might include some pure documentation fixes.
  • Bug reports are usually closed as fixed when the relevant PR is merged, but there’s usually a delay before the fix makes it to users’ machines. This means that filtering by date is a very indirect and inexact way to try to capture the correct set of issues (but I don’t have a better one). Some of the fixes in this list might not be available yet, or they might still be in testing.

Now, here are my questions for you and the rest of the Qubes community:

  • Is this list useful?
  • Is it better than nothing, or does it do more harm than good?
  • Should I include this type of link in future announcements like this one?
  • Do you see any way to improve the filters?

I understand that a filtered list like this one is less than ideal. The ideal solution would be to have a human (or group of them) go through every single issue that might be relevant to the release, go through all the code changes in each release, and write a curated list of exactly the relevant fixes. Unfortunately, there’s no one available who has the required combination of expertise, time, and willingness to do that. If anyone can think of a better solution, please let us know.

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Simply clicking on a random good first issue flag winnowed the four page list down to a single page. With additional filtering available upon simple mouse clicks, I’d say continue to include the list since it provides a meaningful ability to focus potential contributions.

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@adw

Now, here are my questions for you and the rest of the Qubes community:

  • Is this list useful?
  • Is it better than nothing, or does it do more harm than good?
  • Should I include this type of link in future announcements like this one?

Yes x3.

  • Do you see any way to improve the filters?

Perhaps if there is a tag “documentation”, you may be able to filter out those too.

Unfortunately, there’s no one available who has the required combination of expertise, time, and willingness to do that.

Where is our friend @alimirjamali? Haven’t read anything from him for a while.

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alimirjamali is from Iran, I guess it is not so easy there right now.

@alimirjamali if you read this and need help, let us know.

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I agree with qubist that this is all very useful, yes x3.

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@phceac request and @adw answer are great!

Not really, because, as @adw said, you can have several labels, including “C: doc” but the issue is still a bug in the OS. With the filter for r4.3.1 it’s only one issue.

Yes, the internet blackout is one reason. I was thinking about him too when I read “a human” :slight_smile: The newsletter was a very useful resource, and I suspect that we wouldn’t have cared that much about the “many bug fixes” with it.

We could try to write some kind of community release notes: when you’re involved in an issue, write some kind of note about it. I.e.:

The two following issues are closed but I don’t see them:

  • preloaded disposables are explained in tools showing them (issue #10639)
  • the --app argument of qubesctl has been renamed to --apps (issue #6403)
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As mentioned above, some issues have the C: doc label, but they also have another category label, such as C: core. For example, the issue could be “Fix this bug in the core code and document it.” If we were to filter out all issues with the C: doc label, we would filter such issues out, even when it’s primarily a code change with just a minor doc edit tacked on. Presumably, we would not want those filtered out.

Thanks for your feedback, all. I’ll edit this announcement to include the link and include a similar one in future announcements when it makes sense to do so.

Our thoughts are with you, @alimirjamali. Hope you’re safe and well.

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I add my expression of pleasure to have this list available.

It seems a good compromise - to avoid a lot of release documentation work, that is rapidly irrelevant, but to still give a handle on what is changing.

There are some issues that I find a little opaque, but probably it is only because I did not look down to patch level, and would not understand the changes if I did (e.g. at least one “openqa regressions” issue). It is not a problem for me.

So… big thanks to @adw, and all the rest of the Qubes team, and other contributors.

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I got a message from him, few days ago, saying he’s fine. I can’t authenticate the message but it is sufficient for me, given the situation.

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Hi. Thank you very much for your kind words and thanks to anyone else who has inquired about my well-being. My internet connectivity is still very limited. I hope to be able to resume Qubes OS related activity somewhere in near future if nothing goes wrong again.

BTW, I can sign a message via GPG/PGP if necessary :wink:

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@alimirjamali

Peace be upon you!

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No need to. I just felt like I had to mention that before making a public announcement :slight_smile:

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Hi. Thank you very much for your kind words and thanks to anyone else
who has inquired about my well-being. My internet connectivity is
still very limited. I hope to be able to resume Qubes OS related
activity somewhere in near future if nothing goes wrong again.

Yo, welcome back!

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I’ve tried the latest ISOs (including weekly release ISO from qubes.notset.fr), and wondered why sys-usb isn’t working within my qubes.

it turns out adding a bit of RAM capacity(300M → 400M) in legacy hardware helps fixing the issue, it seems updates or recent linux kernel demands more ram to initiate. without sufficient amount of ram, i had to see qrexec failed to initiate the qube despite of the properly recognized usb devices.

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How do I install 4.3.1?

I currently have version 4.3 on my laptop!

I can’t find anything here!

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Use qubes-update.

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4.3.1 hasn’t been released yet. This announcement is about 4.3.1-rc1, which is a release candidate (RC) – a type of testing release. If you don’t want to test 4.3.1-rc1, you don’t have to do anything.

Once 4.3.1 has been released, we will make an announcement. All you will have to do to upgrade from 4.3 to 4.3.1 is continue to update normally.

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So great to hear from you!

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