Linux Journal - The Original Magazine of the Linux Community

Thunderbird 156 Released with OAuth Improvements, OpenPGP Updates, and Major Linux Fixes

George Whittaker — Tue, 15 Sep 2026 16:00:00 +0000

The Thunderbird team has officially released Thunderbird 156, bringing another round of new features, security improvements, authentication enhancements, and reliability fixes to the popular open-source email client. Released on September 15, 2026, the update is available for Linux alongside Windows and macOS.

Thunderbird 156 is not a dramatic redesign of the desktop mail client. Instead, it concentrates on improving areas that matter to everyday users and system administrators, including OAuth authentication, OpenPGP, POP3, IMAP, Exchange Web Services, SMTP, attachments, calendars, enterprise policies, and security.

For Linux users in particular, the release delivers several fixes affecting common mail protocols and account configurations while retaining support for Linux environments using GTK+ 3.14 or newer.

Thunderbird 156 Arrives on Linux

Thunderbird 156 follows version 154, which arrived in August with features including optional system tray operation and Microsoft Graph support for Microsoft 365.

Version 156 continues the project's monthly release cycle with a more targeted collection of authentication, security, compatibility, and reliability improvements.

According to Thunderbird's official release notes, version 156 requires:

Linux: GTK+ 3.14 or newer
Windows: Windows 10 or newer
macOS: macOS 10.15 or newer

Thunderbird 156 was officially released on September 15.

Linux distribution availability will vary because distributions can package Thunderbird according to their own schedules. Users receiving Thunderbird through another packaging channel may therefore see version 156 at a different time.

Custom OAuth Support Expands

One of the most significant areas of development in Thunderbird 156 is OAuth authentication.

Thunderbird now supports custom OAuth configurations containing an issuer ID and client secret for IMAP and POP3 accounts. Custom OAuth support has also been extended specifically to POP3.

OAuth has become increasingly important as email providers move away from conventional username-and-password authentication toward token-based authentication.

For Thunderbird, broader custom OAuth support means users and organizations have greater flexibility when connecting the client to mail services that don't fit Thunderbird's predefined provider configurations.

This can be particularly useful in enterprise environments, self-hosted infrastructure, and organizations operating their own identity systems.

Exchange Custom OAuth Setup Fixed

Exchange users receive an important related correction.

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KDE Plasma 6.7.5 Released with Discover, KWin, Wayland, and HDR Fixes

George Whittaker — Thu, 10 Sep 2026 16:00:00 +0000

by George Whittaker

The KDE Project has officially released KDE Plasma 6.7.5, delivering another round of bug fixes and stability improvements for the Plasma 6.7 desktop series. Released on September 8, 2026, the update contains roughly a month of fixes and updated translations contributed since Plasma 6.7.4 arrived in early August.

Unlike a major Plasma release, version 6.7.5 doesn't introduce a large collection of new desktop features. Instead, KDE has focused on fixing problems affecting Discover, KWin, Wayland, networking, System Monitor, Plasma Desktop, RPM-OSTree systems, Snap updates, HDR rendering, and several other components.

For users already running Plasma 6.7, this makes version 6.7.5 primarily a maintenance upgrade intended to make the desktop more dependable ahead of the next major Plasma series.

KDE Plasma 6.7.5 Arrives as the September Bugfix Release

KDE describes Plasma 6.7.5 as its September bugfix release for the Plasma 6 desktop.

The broader Plasma 6.7 series originally arrived in June 2026, followed by a succession of maintenance releases:

Plasma 6.7.1 on June 23
Plasma 6.7.2 on June 30
Plasma 6.7.3 on July 14
Plasma 6.7.4 on August 4
Plasma 6.7.5 on September 8

KDE's official download infrastructure confirms that the Plasma 6.7.5 source packages became available on September 8.

This slower maintenance cadence later in a Plasma series is normal. Once the most urgent post-release problems have been addressed, KDE generally shifts more development attention toward the next feature release while continuing to provide important fixes for the current branch.

Discover Receives Several Important Fixes

KDE's Discover software center receives some of the most noticeable improvements in Plasma 6.7.5.

One particularly annoying problem could cause Discover to become stuck while checking for updates when its Snap backend was installed but no Snap applications actually had updates available.

That problem has now been corrected.

Discover also behaves more reliably when fwupd, the Linux firmware update service, is unavailable. Previously, a broken or intentionally masked fwupd service could interfere with Discover's normal operation. Plasma 6.7.5 allows the rest of the application to continue functioning correctly in that situation.

This is useful for systems where firmware updating isn't supported, where administrators intentionally disable the service, or where fwupd encounters a configuration problem.

Firmware Updates No Longer Incorrectly Require Reboots

Another Discover correction addresses a regression involving firmware updates.

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Slackware 16 Alpha 1 Released with Linux 6.18 LTS, GCC 16.2, and Plasma 6

George Whittaker — Tue, 08 Sep 2026 16:00:00 +0000

by George Whittaker

One of Linux's oldest surviving distributions is moving closer to its next major release. Slackware 16 Alpha 1 became available on September 5, 2026, marking the first formal alpha milestone on the road toward Slackware Linux 16. The release follows a major rebuild of Slackware-current using a substantially newer GNU toolchain and brings together several upgrades that have accumulated since Slackware 15.0 arrived more than four years ago.

The alpha combines Linux 6.18 LTS, GCC 16.2.0, glibc 2.44, GNU Binutils 2.47, KDE Plasma 6, and numerous updated user-space packages while retaining much of the deliberately traditional architecture that has distinguished Slackware for decades.

For longtime Slackware users, Alpha 1 is particularly significant because it provides the clearest indication yet that the lengthy Slackware 16 development cycle is moving toward an eventual stable release.

Slackware 16 Finally Reaches Alpha

Slackware doesn't operate according to the predictable six-month or annual release schedules used by many other Linux distributions.

Instead, development takes place continuously through the Slackware-current branch. Patrick Volkerding and other contributors update that development tree until it reaches a state considered suitable for a stable release.

The previous major version, Slackware 15.0, was released in February 2022. More than four and a half years later, Slackware-current has now officially reached the first alpha milestone for version 16.

Volkerding marked the milestone following a complete rebuild of the distribution with its newly upgraded compiler, C library, and binary utilities.

The short changelog announcement even suggested there might finally be "a light at the end of the tunnel," a promising indication for Slackware users waiting for version 16.

The Entire Distribution Was Rebuilt

One of the most consequential changes behind Alpha 1 is a complete package rebuild.

Slackware's development toolchain has moved to:

GCC 16.2.0
glibc 2.44
GNU Binutils 2.47

After introducing those components, Slackware rebuilt the distribution's packages against the updated environment.

A full rebuild is much more significant than simply replacing three packages.

GCC is responsible for compiling much of the software distributed with Slackware, glibc provides fundamental C library functionality used throughout Linux user space, and Binutils supplies essential development utilities including the GNU assembler and linker.

Rebuilding the distribution against these versions gives Slackware 16 a considerably newer foundation than its predecessor.

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Top AEO Tools for Linux and Developer Documentation Teams

Malana VanTyler — Thu, 03 Sep 2026 16:00:00 +0000

by Malana VanTyler

These platforms help teams monitor how technical content appears in AI-generated answers, from brand mentions and citations to accuracy and referral traffic.

Search is splitting into two experiences: one built around ranked pages and another around generated answers. As AI platforms summarize Linux tutorials, open-source project documentation, API references and technical guidance, teams need ways to measure whether their content is mentioned, cited and accurately represented.

An AEO platform provides that visibility. They help writers, maintainers, developers, and content teams examine how pages appear in generated answers, which sources receive citations, and whether AI platforms send traffic to the intended documentation.

AI Security Is Now a Core Part of Linux Infrastructure

Malana VanTyler — Tue, 01 Sep 2026 16:00:00 +0000

by Malana VanTyler

AI security means hardening everything around the model, not just the model itself.

AI workloads have moved out of the research sandbox and into production, which means they now carry the same operational weight as any other critical service. If you want to understand what is AI security in practical terms, start here. It's not a

separate discipline bolted onto your existing stack. It's an extension of it. The systems around a model matter as much as the model itself, and for teams running Linux and open-source infrastructure, that means applying familiar discipline to some new risks.

AI Security Is Becoming Part of the Linux Infrastructure

Treat AI workloads like production infrastructure, not side projects. A model doesn't run in isolation. It depends on an operating system, a container runtime, storage, APIs, identity systems, and a pile of dependencies. If any of those layers are weak, prompt filtering or output moderation won’t be enough.

Security teams that only look at the model may miss much of the actual attack surface. The work starts with the same questions you'd ask about any service. What's exposed? Who can reach it? What happens if it's compromised?

The AI Attack Surface Extends Beyond the Model

Model-serving APIs, embeddings, retrieval systems, vector databases, plugins, and CI/CD pipelines all now sit inside the perimeter. A vector database that holds proprietary documents is a data store like any other and needs the same access controls. An inference endpoint that accepts arbitrary text input is a public-facing service, and it needs rate limits and authentication like any other. Plugins and tool integrations expand what a model can touch, which also expands what an attacker can touch. It’s the same threat modeling you’d apply to a web application.

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The New Way Security Teams Evaluate Pentesting Vendors

George Whittaker — Thu, 27 Aug 2026 16:00:00 +0000

by George Whittaker

Why security buyers are rethinking what matters most.

Security teams typically don’t struggle to find vulnerabilities as much as they have in the past. The harder part usually begins after the report arrives, once dozens of findings land in front of engineering teams already juggling patch schedules, production deadlines, and internal disagreements about urgency. Platforms like XBOW, OffSec, and Cobalt have entered that environment as organizations started rethinking what they actually need from pentesting vendors beyond annual compliance exercises.

A vulnerability may look severe inside a dashboard, while no one internally agrees whether it creates meaningful exposure or simply adds another item to an already crowded queue. Infrastructure also changes too quickly for static testing cycles to answer every operational question.

APIs update mid-quarter, contractors receive temporary access that lingers longer than expected, and cloud permissions change quietly during routine development work. Buyers evaluating vendors now spend more time asking whether testing accurately reflects the systems employees use every day.

Pentesting Vendors Now Face Different Expectations

Long reports stopped carrying the same weight years ago. Security teams already know modern environments contain weaknesses. What many organizations want now is clearer evidence showing which findings deserve immediate attention and which ones can wait without creating major operational exposure. That distinction became harder to ignore as remediation timelines stretched across larger environments.

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New Linux “Steal Governor” Targets CPU Contention in Overcommitted Virtual Machines

George Whittaker — Tue, 25 Aug 2026 16:00:00 +0000

by George Whittaker

Linux kernel developers are considering a new “steal governor” designed to improve performance when multiple virtual machines compete for limited physical CPU resources. The proposal uses the amount of CPU steal time observed inside a guest to dynamically reduce or expand the number of virtual CPUs on which that VM prefers to schedule work.

The feature is primarily aimed at heavily virtualized servers where administrators deliberately assign more virtual CPUs than the host can physically execute at once. Under heavy load, that overcommitment can lead to frequent vCPU preemption, lock-holder delays, cache disruption, and ultimately lower overall throughput.

The latest v11 patch series was posted on August 25, 2026, and its developer has proposed consideration during the Linux 7.3 development cycle, potentially targeting Linux 7.4 for inclusion. This means the feature is still under review and is not part of a stable Linux kernel yet.

What Is CPU Steal Time?

CPU steal time is a concept specific to virtualization.

Imagine a virtual machine has eight vCPUs. From inside that VM, the operating system behaves as though those eight CPUs are available. But those virtual CPUs ultimately need to run on the host's physical processors.

If several VMs are competing for the same physical CPU resources, the hypervisor may temporarily prevent one VM's vCPU from running so another VM can use the processor.

The time during which the guest wanted to execute but couldn't because the hypervisor was using the underlying CPU elsewhere is known as steal time.

High steal time is therefore a useful indication that the physical host is experiencing CPU contention.

The “Noisy Neighbor” Problem

The steal governor is designed primarily to address what virtualization engineers commonly call the noisy neighbor problem.

Consider a server hosting several VMs:

VM A has 32 vCPUs.
VM B has 32 vCPUs.
VM C has 32 vCPUs.
The physical server has only 64 CPU threads available to those workloads.

That configuration can work perfectly well when the VMs aren't simultaneously busy.

If all three suddenly become heavily loaded, however, they may collectively request more CPU time than the physical machine can provide.

The hypervisor then has to constantly switch between vCPUs.

Those interruptions can become particularly expensive if a vCPU is preempted while holding a lock or executing another latency-sensitive section of code. Other threads may then wait for a vCPU that isn't currently being allowed to run.

The result can be counterintuitive: giving the VMs more virtual CPUs can sometimes make the combined workloads slower.

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Thunderbird 154 Released with System Tray Mode, Microsoft Graph Support, and Major Mail Fixes

George Whittaker — Thu, 20 Aug 2026 16:00:00 +0000

by George Whittaker

The Thunderbird team has officially released Thunderbird 154, delivering several useful new features alongside a substantial collection of fixes for email, calendars, address books, authentication, and stability. Released on August 18, 2026, Thunderbird 154 is now the latest monthly release of the popular open-source email client.

For Linux users, one of the most interesting additions is a new optional system tray mode, while Microsoft 365 users gain Microsoft Graph support. The release also improves global search, attachment handling, IMAP reliability, Exchange authentication, and CalDAV synchronization.

New Optional System Tray Mode

One of Thunderbird 154's most welcome additions is an optional system tray mode.

When enabled, closing Thunderbird's last window no longer needs to completely terminate the application. Instead, Thunderbird can remain running in the background through the system tray.

This can be particularly useful for users who want Thunderbird available throughout the day without keeping its main window open.

For Linux desktop users, the feature could make Thunderbird feel more like a traditional background email client, especially on desktops where tray-based applications remain part of the normal workflow.

Microsoft Graph Enabled for Microsoft 365

Thunderbird 154 also enables Microsoft Graph for Microsoft 365.

Microsoft Graph is Microsoft's API platform for accessing Microsoft 365 services and data. Its integration is particularly important as Thunderbird continues improving its support for Exchange and Microsoft-hosted email environments.

Thunderbird has been steadily expanding its Microsoft ecosystem compatibility, making the open-source client increasingly practical for users who need to access workplace Microsoft 365 accounts from Linux.

Global Search Gets a Useful New Option

Thunderbird's global search functionality also receives an improvement.

Users can now configure global search results to open in list view by default, providing another option for people who prefer a more traditional message-list workflow when reviewing search results.

It's a relatively small addition, but one that can make repeated searches more convenient for users managing large mailboxes.

Better Attachment Management

Thunderbird 154 introduces several improvements for handling email attachments.

A new "Copy To" folder context menu has been added for message/rfc822 attachments, and these attached messages can now be dragged directly into Thunderbird's folder tree.

These changes should make it easier to organize attached email messages without having to use additional steps or workarounds.

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Linux Kernel 7.2 Officially Released with Cache-Aware Scheduling, USB4STREAM, and Major AMD Improvements

George Whittaker — Tue, 18 Aug 2026 16:00:00 +0000

by George Whittaker

Linux creator Linus Torvalds has officially released Linux Kernel 7.2, opening another chapter in the development of the world's most widely deployed open-source kernel. The final release arrived on August 16, 2026, following seven release candidates and roughly two months of development. Kernel.org now lists Linux 7.2 as the latest mainline release.

Linux 7.2 is a substantial update with improvements spanning CPU scheduling, storage performance, AMD and Intel hardware support, graphics, networking, virtualization, RISC-V, and Apple Silicon. Among its biggest additions are Cache-Aware Scheduling, USB4STREAM, AMD ISP4 support, and initial AMDGPU HDMI 2.1 FRL functionality.

Cache-Aware Scheduling Lands in Linux

One of the most interesting performance additions in Linux 7.2 is Cache-Aware Scheduling (CAS).

Modern processors frequently contain multiple last-level caches shared between groups of CPU cores. Traditional scheduling decisions don't always account optimally for those cache relationships, potentially moving tasks between cores in ways that increase cache misses.

Cache-Aware Scheduling gives the Linux scheduler additional information about cache topology so it can make smarter decisions about where workloads should run.

Early testing during development produced particularly impressive results for some server workloads, including major gains in certain MySQL configurations. The improvement varies significantly by hardware and workload, so users shouldn't expect similarly dramatic gains everywhere.

For modern AMD and Intel systems with increasingly complex CPU topologies, however, CAS provides another tool for extracting better performance from existing hardware.

USB4STREAM Enables High-Speed Connections Between Computers

Linux 7.2 also introduces USB4STREAM, an interesting new capability for transferring data directly between computers over USB4 or Thunderbolt connections.

Rather than treating USB primarily as a traditional host-to-device interface, USB4STREAM can facilitate high-speed communication between systems.

Potential applications include:

Large file transfers
Development environments
High-speed system-to-system networking
Debugging
Specialized workstation workflows

With USB4 and Thunderbolt increasingly common on laptops and desktops, this could eventually become a useful option for moving large amounts of data between Linux machines.

AMD ISP4 Finally Reaches the Mainline Kernel

AMD users receive another important addition with the arrival of the AMD ISP4 driver.

ISP stands for Image Signal Processor, hardware responsible for processing camera data before it reaches applications.

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Linux 7.2 Reverts DRM Scheduler Change After Serious GPU Regressions

George Whittaker — Thu, 13 Aug 2026 16:00:00 +0000

by George Whittaker

Linux kernel developers made a significant last-minute graphics change for Linux 7.2, reverting the DRM GPU scheduler back to its previous FIFO policy by default after the newer fair scheduling implementation caused serious performance regressions. The revert was submitted just before the final Linux 7.2 release after users reported severe slowdowns and desktop freezes under sustained GPU workloads.

The decision demonstrates the kernel community’s conservative approach to regressions: when a new feature causes problems this late in a development cycle, restoring known-good behavior can be safer than rushing an incomplete fix.

What Changed in Linux 7.2?

Earlier in the Linux 7.2 development cycle, the DRM subsystem switched its default GPU scheduling policy to a new fair scheduler.

The goal was to distribute GPU execution time more fairly between competing workloads. Instead of relying on the established FIFO scheduling behavior, the new implementation uses a fairness-oriented approach designed to prevent one workload from dominating GPU resources.

However, real-world testing exposed problems that had not appeared during earlier development.

The final DRM fixes for Linux 7.2 therefore:

Revert the fair scheduler changes
Restore FIFO as the default
Restore selectable scheduling policies
Mark the fair scheduling policy as experimental

DRM maintainer Dave Airlie acknowledged that developers may have moved too aggressively when switching to the new scheduler.

AMD Radeon Gaming Exposed the Regression

The problem became particularly noticeable during gaming on an AMD Radeon RX 9070 XT.

A regression report described severe performance degradation when the GPU remained close to 100% utilization. A game running through Proton could drop to roughly 10 FPS or freeze, while audio continued playing normally.

The problem could become severe enough that the entire KDE Plasma Wayland session stopped responding, sometimes requiring the compositor to be killed or the computer to be rebooted.

Interestingly, reducing GPU load—such as by opening an in-game menu or switching away from the game—could immediately stop the stuttering.

FIFO Worked, FAIR Did Not

Testing provided strong evidence that the new scheduling policy was responsible.

The reporter compared Linux 7.2 release candidates using FAIR against configurations using the previous FIFO policy. Under otherwise similar conditions:

FAIR: reproduced the performance problem.

FIFO: survived extended stress testing without the regression.

Linux 7.1.x also behaved normally.

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Linux Journal - The Original Magazine of the Linux Community

Thunderbird 156 Released with OAuth Improvements, OpenPGP Updates, and Major Linux Fixes

Thunderbird 156 Arrives on Linux

Custom OAuth Support Expands

Exchange Custom OAuth Setup Fixed

KDE Plasma 6.7.5 Released with Discover, KWin, Wayland, and HDR Fixes

KDE Plasma 6.7.5 Arrives as the September Bugfix Release

Discover Receives Several Important Fixes

Firmware Updates No Longer Incorrectly Require Reboots

Slackware 16 Alpha 1 Released with Linux 6.18 LTS, GCC 16.2, and Plasma 6

Slackware 16 Finally Reaches Alpha

The Entire Distribution Was Rebuilt

Top AEO Tools for Linux and Developer Documentation Teams

Top AEO Tools for Technical Content

AI Security Is Now a Core Part of Linux Infrastructure

AI Security Is Becoming Part of the Linux Infrastructure

The AI Attack Surface Extends Beyond the Model

The New Way Security Teams Evaluate Pentesting Vendors

Pentesting Vendors Now Face Different Expectations

New Linux “Steal Governor” Targets CPU Contention in Overcommitted Virtual Machines

What Is CPU Steal Time?

The “Noisy Neighbor” Problem

Thunderbird 154 Released with System Tray Mode, Microsoft Graph Support, and Major Mail Fixes

New Optional System Tray Mode

Microsoft Graph Enabled for Microsoft 365

Global Search Gets a Useful New Option

Better Attachment Management

Linux Kernel 7.2 Officially Released with Cache-Aware Scheduling, USB4STREAM, and Major AMD Improvements

Cache-Aware Scheduling Lands in Linux

USB4STREAM Enables High-Speed Connections Between Computers

AMD ISP4 Finally Reaches the Mainline Kernel

Linux 7.2 Reverts DRM Scheduler Change After Serious GPU Regressions

What Changed in Linux 7.2?

AMD Radeon Gaming Exposed the Regression

FIFO Worked, FAIR Did Not