What you need to know
Debian’s release pages say Debian 11 (bullseye) reached the end of Long Term Support on August 31, 2026, while Debian 12 (bookworm) ended full support on July 11, 2026 and has LTS until June 30, 2028 on a reduced set of architectures. Debian 13 (trixie) has superseded Debian 12.
Potentially affected
Organizations running Debian 11 or 12 on servers, virtual machines, containers or appliances, and the vendors who ship Debian-based systems.
DSE recommendation
DSE recommends upgrading or replacing Debian 11 systems now and scheduling Debian 12 systems for Debian 13 well before bookworm’s LTS ends on June 30, 2028.
Debian’s release pages say Debian 11 (bullseye) reached the end of Long Term Support on August 31, 2026, while Debian 12 (bookworm) ended full support on July 11, 2026 and has LTS until June 30, 2028 on a reduced set of architectures. Debian 13 (trixie) has superseded Debian 12.
Source facts
Debian’s bullseye release page says the Debian 11 life cycle encompassed five years: three years of full Debian support until August 14th, 2024, and two years of Long Term Support until August 31st, 2026, with LTS limited to the i386, amd64, armhf and arm64 architectures. It notes that third parties offer paid security support for bullseye up to June 30th, 2031.
The bookworm release page says Debian 12 has been superseded by Debian 13 (trixie), with full Debian support until July 11th, 2026 and LTS until June 30th, 2028. Its LTS is limited to i386, amd64, armhf, arm64 and ppc64el, and all other architectures are no longer supported in bookworm.
Debian’s LTS page says LTS is handled not by the Debian security team but by a separate group of volunteers and companies. The security FAQ says the security team supports a stable distribution for three years after its release, and that contrib, non-free and non-free-firmware packages are not supported by the security team.
Applicability
Use this for any Debian system, including appliances whose vendor builds on Debian. An appliance vendor’s own support policy governs its product, so confirm the vendor’s update commitments rather than assuming Debian’s dates apply.
DSE recommendation
DSE recommends upgrading or replacing Debian 11 systems now and scheduling Debian 12 systems for Debian 13 well before bookworm’s LTS ends on June 30, 2028. Record each system’s release and architecture, check for packages from contrib or non-free that receive no security support, test upgrades on a copy or snapshot first, and isolate any Debian 11 system that must stay online until replaced.
Verification
Run a fleet report of Debian release versions each quarter, confirm security updates are still being installed, and track remaining Debian 11 systems to zero.
Official references
Debian — Debian “bullseye” Release Information. Debian — Debian “bookworm” Release Information. Debian — Debian Long Term Support. Debian — Debian security FAQ. Reviewed October 18, 2026.
Review the official source
Debian — Debian “bullseye” Release Information · Verified October 18, 2026
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