Ubuntu Core 26 Delivers Leaner Updates and ARM64 Live Kernel Patching

Introduction

Canonical has officially released Ubuntu Core 26, the latest long-term support (LTS) version of its immutable, snap-based operating system designed for IoT and edge devices. This release introduces significant improvements in update efficiency and security, including a dramatic reduction in over-the-air (OTA) update sizes and the extension of live kernel patching to ARM64 architectures. These enhancements promise to streamline device management, reduce bandwidth consumption, and bolster security for embedded systems.

Ubuntu Core 26 Delivers Leaner Updates and ARM64 Live Kernel Patching — Source: www.omgubuntu.co.uk

Smaller OTA Updates with Snap-Delta Format

One of the most impactful changes in Ubuntu Core 26 is the introduction of a new snap-delta format that slashes the size of over-the-air updates by up to 90% for most snaps. This reduction is achieved by delivering only the changed portions of a snap package rather than the entire file. For example, updates to the Core base snaps drop from approximately 16 MB to just 1.5 MB, representing a staggering 90% decrease. This means devices with limited connectivity or metered data plans can receive vital updates more quickly and cost-effectively.

The snap-delta mechanism works by comparing the current installed snap version with the target version and constructing a binary diff. Clients then apply this delta to transform their local snap into the new version. This approach not only reduces download sizes but also minimizes storage requirements on the device itself. For fleet operators, the cumulative effect can translate into gigabytes of saved bandwidth and faster update rollouts across thousands of devices.

Impact on IoT Deployments

For Internet of Things (IoT) deployments where network conditions are often constrained, smaller OTA updates are a game-changer. Devices in remote locations or on low-power wide-area networks (LPWAN) can now receive security patches and feature updates without overwhelming the network. Additionally, the reduced size lowers the risk of update failures due to intermittent connectivity, improving overall reliability.

Faster Installation with Optimized Boot

Ubuntu Core 26 also accelerates the installation process by eliminating redundant reboots during provisioning. The installer now uses an initramfs-based approach that configures the system fully before the first boot, meaning the device only needs to restart once to enter production mode. In earlier versions, multiple reboots were required as each stage of installation completed, consuming time and power. This improvement can reduce provisioning times by minutes, which is critical for high-volume manufacturing or rapid device replacement scenarios.

ARM64 Live Kernel Patching

Perhaps the most notable security enhancement in Ubuntu Core 26 is the extension of live kernel patching to ARM64 devices. Livepatch, a feature previously available only on x86 architectures, allows critical and high-severity kernel security fixes to be applied without rebooting the device. This is especially valuable for ARM64-based IoT gateways, smart cameras, and edge servers where uptime is paramount.

With Livepatch enabled, vulnerability patches are applied on-the-fly by modifying the running kernel's code in memory. Devices remain operational during the patching process, avoiding service interruptions. For fleets that require 99.99% uptime—such as industrial controllers or medical devices—this capability is a significant operational advantage. Canonical provides a limited number of free Livepatch subscriptions, with paid plans for larger deployments.

Enabling Livepatch on Ubuntu Core 26

To activate Livepatch on ARM64 devices running Ubuntu Core 26, administrators need to connect the device to their Ubuntu One account and install the canonical-livepatch snap. Commands such as snap install canonical-livepatch followed by sudo canonical-livepatch enable will initiate the service. Once enabled, patches are delivered automatically via the snap-delta mechanism as part of regular OTA updates.

Conclusion

Ubuntu Core 26 represents a meaningful step forward for immutable, containerized operating systems in the IoT and edge computing space. By reducing OTA update sizes by up to 90% via snap-delta, speeding up provisioning with a single-reboot installer, and finally offering live kernel patching on ARM64, Canonical addresses three of the most pressing challenges in embedded device management: bandwidth constraints, time-to-deployment, and security continuity. These improvements make Ubuntu Core 26 an even more attractive choice for developers and operators building resilient, scalable, and secure device ecosystems.

For more details, visit the official Ubuntu Core website or read the release notes.