Let's Encrypt has published a retrospective that covers the decade since it published its first publicly trusted certificate in September 2015:

In March 2016, we issued our one millionth certificate. Just two years later, in September 2018, we were issuing a million certificates every day. In 2020 we reached a billion total certificates issued and as of late 2025 we're frequently issuing ten million certificates per day. We're now on track to reach a billion active sites, probably sometime in the coming year.

Greg Kroah-Hartman is writing a series of blog posts about Linux becoming a Certificate Numbering Authority (CNA):

It's been almost 2 full years since Linux became a CNA (Certificate Numbering Authority) which meant that we (i.e. the kernel.org community) are now responsible for issuing all CVEs for the Linux kernel. During this time, we've become one of the largest creators of CVEs by quantity, going from nothing to number 3 in 2024 to number 1 in 2025. Naturally, this has caused some questions about how we are both doing all of this work, and how people can keep track of it.

So far, Kroah-Hartman has published the introductory post, as well as a detailed post about kernel version numbers that is well worth reading.

Linux containers have made it reasonably easy to develop, distribute, and deploy server applications along with all the distribution dependencies that they need. For example, anyone can deploy and run a Debian-based PostgreSQL container on a Fedora Linux host. Distrobox is a project that is designed to bring the cross-distribution compatibility to the desktop and allow users to mix-and-match Linux distributions without fussing with dual-booting, virtual machines, or multiple computers. It is an ideal way to install additional software on image-based systems, such as Fedora's Atomic Desktops or Bazzite, and also provides a convenient way to move a development environment or favorite applications to a new system.

(Stay tuned for details in our Maintainers Summit coverage.)

One of the things that has historically stood between Linux and the fabled "year of the Linux desktop" is its lack of support for video games. Many users who would have happily abandoned Windows have, reluctantly, stayed for the video games or had to deal with dual booting. In the past few years, though, Linux support for games—including those that only have Windows versions—has improved dramatically, if one is willing to put the pieces together. Bazzite, an image-based Fedora derivative, is a project that aims to let users play games and use the Linux desktop with almost no assembly required.

Version 146.0 of the Firefox web browser has been released. One feature of particular interest to Linux users is that Firefox now natively supports fractional scaled displays on Wayland. Firefox Labs has also been made available to all users even if they opt out of telemetry or participating in studies. "This means more experimental features are now available to more people."

This release also adds support for Module-Lattice-Based Key-Encapsulation Mechanism (ML-KEM) for WebRTC. ML-KEM is "believed to be secure against attackers with large quantum computers". See the release notes for all changes.

The Internet Engineering Task Force (IETF) is the standards body responsible for the TLS encryption standard — which your browser is using right now to allow you to read LWN.net. As part of its work to keep TLS secure, the IETF has been entertaining proposals to adopt "post-quantum" cryptography (that is, cryptography that is not known to be easily broken by a quantum computer) for TLS version 1.3. Discussion of the proposal has exposed a large disagreement between participants who worried about weakened security and others who worried about weakened marketability.

Jon Seager, VP of engineering for Canonical, has announced a plan to develop a universal Public Key Infrastructure tool called upki:

Earlier this year, LWN featured an excellent article titled "Linux's missing CRL infrastructure". The article highlighted a number of key issues surrounding traditional Public Key Infrastructure (PKI), but critically noted how even the available measures are effectively ignored by the majority of system-level software on Linux.

One of the motivators for the discussion is that the Online Certificate Status Protocol (OCSP) will cease to be supported by Let's Encrypt. The remaining alternative is to use Certificate Revocation Lists (CRLs), yet there is little or no support for managing (or even querying) these lists in most Linux system utilities.

To solve this, I'm happy to share that in partnership with rustls maintainers Dirkjan Ochtman and Joe Birr-Pixton, we're starting the development of upki: a universal PKI tool. This project initially aims to close the revocation gap through the combination of a new system utility and eventual library support for common TLS/SSL libraries such as OpenSSL, GnuTLS and rustls.

No code is available as of yet, but the announcement indicates that upki will be available as an opt-in preview for Ubuntu 26.04 LTS. Thanks to Dirjan Ochtman for the tip.

Greg Kroah-Hartman has announced the release of the 6.17.11, 6.12.61, 6.6.119, 6.1.159, 5.15.197, and 5.10.247 stable kernels. Each contains important fixes throughout the tree; users of these kernels should upgrade.

Emma Smith and Kirill Podoprigora, two of Python's core developers, have opened a discussion about including Rust code in CPython, the reference implementation of the Python programming language. Initially, Rust would only be used for optional extension modules, but they would like to see Rust become a required dependency over time. The initial plan was to make Rust required by 2028, but Smith and Podoprigora indefinitely postponed that goal in response to concerns raised in the discussion.

Version 3.23.0 of Alpine Linux has been released. Notable changes in this release include an upgrade to version 3.0 of the Alpine Package Keeper (apk), and replacing the linux-edge package with linux-stable:

For years, linux-lts and linux-edge grew apart and developed their own kernel configs, different architectures, etc.

Now linux-edge gets replaced with linux-stable which has the identical configuration as linux-lts, but follows the stable releases instead of the long-term releases (see https://kernel.org/).

The /usr merge planned for this release has been postponed; a new timeline for the change will be published later. See the release notes for more information on this release.

Andreas Schneider has announced version 2.0 of the cmocka unit-testing framework for C:

This release represents a major modernization effort, bringing cmocka firmly into the "modern" C99 era while maintaining the simplicity and ease of use that users have come to expect.

One of the most significant changes in cmocka 2.0 is the migration to C99 standard integer types. The LargestIntegralType typedef has been replaced with intmax_t and uintmax_t from stdint.h, providing better type safety and portability across different platforms. Additionally, we've adopted the bool type where appropriate, making the code more expressive and self-documenting.

Using intmax_t and uintmax_t also allows to print better error messages. So you can now find e.g. assert_int_equal and assert_uint_equal.

cmocka 2.0 introduces a comprehensive set of type-specific assertion macros, including `assert_uint_equal()`, `assert_float_equal()`, and enhanced pointer assertions. The mocking system has also been significantly improved with type-specific macros like `will_return_int()` and `will_return_float()`. The same for parameter checking etc.

LWN covered the project early in its development in 2013. See the full list of new features, enhancements, and bug fixes in cmocka 2.0 in the changelog.