Debian Server 12 Bookworm Update Version 12 (bookworm)

Debian 12 (bookworm) is the new stable release, with 5 years of support, updated core packages, and major installer and upgrade guidance. It adds `non-free-firmware`, reintroduces Secure Boot on ARM64, and changes defaults such as `bookworm-security` and merged-usr only.

• Support for Secure Boot on ARM64 has been reintroduced for UEFI-capable ARM64 hardware.
• The non-free-firmware archive area separates firmware packages from other non-free packages to improve installation image handling.
• The default system clock service is now systemd-timesyncd; chrony and openntpd are also supported.
• Some packages may not receive minimal backports for security issues; Debian notes security support limitations for certain packages.

• Debian Installer includes fixes for graphical support on UTM, the GRUB font loader, the long wait at the end of installation, and BIOS-bootable system detection.
• OpenLDAP 2.5 upgrade may require manual intervention because of incompatible changes; slapd may remain stopped until configuration is updated.
• The new systemd-resolved package is split out and must be installed manually after upgrade if DNS resolution via that service is needed.

• New stable release with updated desktop environments, cloud images, and broad package refresh across the archive.
• New non-free-firmware archive area for firmware packages.
• Debian Med adds shiny-server; Debian Astro adds openvlbi and updates astronomy tools.
• Live images and installation media are available for multiple architectures and desktop environments.

• GRUB packages no longer run os-prober by default.
• Debian 12 supports only the merged-usr root filesystem layout; systems using the old layout are converted during upgrade.
• 32-bit PC (i386) no longer supports i586 processors; i686 is now the minimum requirement.
• Upgrading may encounter conflicts, Pre-Depends loops, immediate configuration errors, or file conflicts that require manual package removal or reinstallation.

• Before upgrading from bullseye, back up /etc, /var/lib/dpkg, /var/lib/apt/extended_states, and dpkg --get-selections '*' output.
• Remove bullseye-backports entries before upgrading and consider adding bookworm-backports afterward.
• Update APT sources to use bookworm-security and review APT pinning or APT::Default-Release settings.
• If you use non-free firmware, add non-free-firmware to APT sources.
• If you rely on systemd-resolved, install the package manually after upgrading.
• Debian 12 can be upgraded in place from Debian 11 bullseye using APT for most configurations.

Product Information

Vendor: Debian

Product: Server

Product type: Software

Application category: Utilities

Platform: Linux

Variant: 12 Bookworm

Version: 12 (bookworm)

Vendor release date: Jun 10, 2023

Original release notes: View on vendor site

Published on updatealert.io: Jul 31, 2026