Umbraco 13 still feels modern. Yet it's approaching its expiry date: on 14 December 2026, support ends for good. Here's what that means in practice — and why postponing costs more than you'd expect.
The facts
Umbraco 13 was released in December 2023 as a Long-Term-Support (LTS) version. An LTS version gets three years of support: first 24 months of full support, then 12 months of security updates only.
- December 2025 — the full support phase ended. No more bug fixes or new features.
- 14 December 2026 — the security phase ends. From then on, no more security updates.
The risk after end-of-life
Once a version reaches end-of-life, Umbraco no longer patches new vulnerabilities. A flaw discovered after that date stays open on your site. Then there's compliance: if you handle personal data, the GDPR expects appropriate technical measures — and running unsupported software is hard to justify.
Why waiting costs more
The leap from 13 to 17 is bigger than an ordinary update (the backoffice has been fully rebuilt since version 14), and near the end of 2026 everyone still on 13 will want to upgrade at once. Start early and you choose your own moment.
What you can do now
Start with an upgrade scan: exactly which version are you on, and which integrations and custom work depend on it? That baseline determines the size of the migration — without committing to anything.