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What's new in Azure Linux 4.0?

Azure Linux 4.0 is the next major release of Microsoft's Linux distribution for Azure. It brings a newer kernel (6.18 LTS), a new package manager (dnf5), and updated core libraries across the stack. For a deeper look at how the operating system (OS) is structured, see the Architecture overview.

Note

Azure Linux 4.0 is now in preview and is strictly limited to evaluation and testing purposes. It's not suitable for production use.

Key components

The following table lists the core component versions included in Azure Linux 4.0:

Component Version Highlights
Kernel 6.18 LTS New hardware drivers, improved Hyper-V integration, GPU/AI accelerator support
glibc 2.42 Performance improvements in string operations, memory allocation, and thread handling
OpenSSL 3.5.4 Modern cryptographic algorithms, deprecated older cipher suites removed
systemd 258.4 Fast boot sequences, improved service management and logging
Python 3 3.14.3 JIT compiler, new syntax features, updated standard library
bash 5.3.9 Scripting improvements and bug fixes
binutils 2.45.1 Modern toolchain
coreutils 9.7 Security fixes and utility improvements
curl 8.15.0 Protocol updates and security patches
util-linux 2.41.3 Updated system utilities
rpm 6.0.1 Modernized database backend, improved signature verification
Package manager dnf5 Faster dependency resolution, lower memory usage
FIPS 140-3 In progress Certification pending; use a certified release for FIPS-required workloads

Package manager: dnf5

Azure Linux 4.0 uses dnf5 as its package manager. dnf5 is a complete rewrite that delivers faster dependency resolution and lower memory usage compared to older package managers.

If you have scripts, Dockerfiles, or CI pipelines that reference tdnf (the package manager used in earlier Azure Linux releases), update those references to dnf5 or dnf before deploying on Azure Linux 4.0.