Breaking changes

None

Breaking changes for preview features

None

Azure Container Linux 3.0 support: Add customization support under the azure-container-linux-3 preview feature, including qcow2, raw, vhd-fixed, vhd, and vhdx output formats; and input.image.path, os.hostname, os.kernelCommandLine, os.additionalFiles, os.additionalDirs, os.groups, os.users, os.modules, os.services, os.uki, os.selinux, os.imageHistory, scripts, output.image, and output.artifacts config API endpoints.

Azure Linux 4.0 support: Add customization support for all CLI commands and configuration endpoints as stable APIs, except the iso, pxe-dir, and pxe-tar output formats and their iso and pxe config API counterparts; and the customize --package-snapshot-time CLI flag and its os.packages.snapshotTime config API counterpart.
Single-partition verity: Add support for placing the data and hash tree on the same partition.
Expanded mkfs.btrfs support: Add support for v6.17.1 through v6.19.1.

UKI addon .cmdline is no longer silently truncated: Build UKI addons with systemd's addonx64.efi.stub instead of linuxx64.efi.stub, so systemd versions with a large linuxx64.efi.stub file do not silently cause truncated .cmdline sections.
Verity reinit no longer drops format settings: Carry over the original verity format settings when reinitializing verity.
setfiles no longer skipped on SELinux-enabled images: On Fedora, Azure Linux 3.0+, and other distributions where SELinux is loaded by default, fall back to /etc/selinux/config to determine mode when selinux= and enforcing= are absent from the kernel command line, instead of assuming SELinux is disabled.
Stale or wrong packages no longer silently installed: Force skip_if_unavailable=False for dnf and tdnf so package operations fail loudly on repo metadata errors instead of silently skipping unreachable repos.
Boot no longer fails on XFS: Use cp --sparse=auto instead of --sparse=always when repartitioning, so legitimate zero runs in vmlinuz aren't converted to sparse holes (which GRUB can't read on XFS).
Kernel cmdline updates no longer fail on images without GRUB_CMDLINE_LINUX: Treat the variable as empty instead of erroring when it's missing from /etc/default/grub.
output.artifacts.items rejects uki-addons value: Now errors on uki-addons, which was previously accepted but had no effect.

Edit-on-GitHub links: Add an "Edit this page on GitHub" link to every doc page, so readers can jump straight to the source markdown to propose improvements.