Dear Qubes Community,
We're pleased to announce the stable release of Qubes OS 4.2.1! This [patch
release](#what-is-a-patch-release) aims to consolidate all the security
patches, bug fixes, and other updates that have occurred since the release of
Qubes 4.2.0. Our goal is to provide a secure and convenient way for users to
install (or reinstall) the latest stable Qubes release with an up-to-date ISO.
The ISO and associated [verification
files](https://www.qubes-os.org/security/verifying-signatures/) are available
on the [downloads](https://www.qubes-os.org/downloads/) page.
## What's new in Qubes OS 4.2.1?
Qubes 4.2.1 includes numerous updates over the initial 4.2.0 release, in
particular:
- All 4.2 dom0 updates to date
- Fedora 39 template
- Linux 6.6.x as the default kernel, significantly reducing the need for
`kernel-latest` on newer systems
For more information about the changes included in this version, see the [full
list of issues completed since the release of
4.2.0](https://github.com/QubesOS/qubes-issues/issues?q=is%3Aissue+is%3Aclosed+reason%3Acompleted+closed%3A2023-12-18..2024-03-14+-label%3A%22R%3A+cannot+reproduce%22+-label%3A%22R%3A+declined%22+-label%3A%22R%3A+duplicate%22+-label%3A%22R%3A+not+applicable%22+-label%3A%22R%3A+self-closed%22+-label%3A%22R%3A+upstream+issue%22+).
## How to get Qubes OS 4.2.1
You have a few different options, depending on your situation:
- If you'd like to install Qubes OS for the first time or perform a clean
reinstallation on an existing system, there's never been a better time to do
so! Simply [download](https://www.qubes-os.org/downloads/) the Qubes 4.2.1 ISO
and follow our [installation
guide](https://www.qubes-os.org/doc/installation-guide/).
- If you're currently on Qubes 4.1, learn [how to upgrade to Qubes
4.2](https://www.qubes-os.org/doc/upgrade/4.2/).
- If you're currently on Qubes 4.2 (including 4.2.0 and 4.2.1-rc1), [update
normally](https://www.qubes-os.org/doc/how-to-update/) (which includes
[upgrading any EOL
templates](https://www.qubes-os.org/doc/how-to-update/#upgrading-to-avoid-eol)
you might have) in order to make your system essentially equivalent to the
stable Qubes 4.2.1 release. No reinstallation or other special action is
required.
In all cases, we strongly recommend [making a full
backup](https://www.qubes-os.org/doc/how-to-back-up-restore-and-migrate/)
beforehand.
## Reminder: new signing key for Qubes OS 4.2
As a reminder, we published the following special announcement in [Qubes Canary
032](https://www.qubes-os.org/news/2022/09/14/canary-032/) on 2022-09-14:
> We plan to create a new Release Signing Key (RSK) for Qubes OS 4.2. Normally,
> we have only one RSK for each major release. However, for the 4.2 release, we
> will be using Qubes Builder version 2, which is a complete rewrite of the
> Qubes Builder. Out of an abundance of caution, we would like to isolate the
> build processes of the current stable 4.1 release and the upcoming 4.2
> release from each other at the cryptographic level in order to minimize the
> risk of a vulnerability in one affecting the other. We are including this
> notice as a canary special announcement since introducing a new RSK for a
> minor release is an exception to our usual RSK management policy.
As always, we encourage you to
[authenticate](https://www.qubes-os.org/security/pack/#how-to-obtain-and-authenticate)
this canary by [verifying its PGP
signatures](https://www.qubes-os.org/security/verifying-signatures/). Specific
instructions are also included in the [canary
announcement](https://www.qubes-os.org/news/2022/09/14/canary-032/).
As with all Qubes signing keys, we also encourage you to
[authenticate](https://www.qubes-os.org/security/verifying-signatures/#how-to-import-and-authenticate-release-signing-keys)
the new Qubes OS Release 4.2 Signing Key, which is available in the [Qubes
Security Pack (qubes-secpack)](https://www.qubes-os.org/security/pack/) as well
as on the [downloads](https://www.qubes-os.org/downloads/) page.
## What is a patch release?
The Qubes OS Project uses the [semantic versioning](https://semver.org/)
standard. Version numbers are written as `..`. 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, 4.2)
inclusive of all updates up to a certain point. (See [supported
releases](https://www.qubes-os.org/doc/supported-releases/) for a comprehensive
list of major and minor releases.) Installing the initial Qubes 4.2.0 release
and fully [updating](https://www.qubes-os.org/doc/how-to-update/) it results in
essentially the same system as installing Qubes 4.2.1. You can learn more about
how Qubes release versioning works in the [version
scheme](https://www.qubes-os.org/doc/version-scheme/) documentation.
This announcement
