Umbraco 17 - The New LTS Standard for Future-Proofing Your Digital Presence
The wait is over! Umbraco 17 has officially landed, and it brings with it the stability, performance, and longevity that SMB and enterprise businesses have been waiting for.
As the latest Long Term Support (LTS) release, Umbraco 17 isn’t just another update - it is the new foundation for the next three years of the Umbraco ecosystem. If you are looking to secure your digital roadmap through 2028, this is the version you need to be on.
What is Umbraco 17?
Released in late November 2025, Umbraco 17 coincides with Microsoft’s release of .NET 10. This alignment is significant because both the CMS and the underlying framework are LTS versions.
Key Benefits of this release:
- Long-Term Stability: As an LTS version, Umbraco 17 comes with 3 years of guaranteed support (bugs and security fixes), ensuring your platform remains secure and compliant until late 2028.
- Performance on .NET 10: Built directly on the newly released .NET 10, your site will benefit from the latest performance benchmarks, faster response times, and better memory management out of the box.
- True Backoffice Load Balancing: A major win for enterprise setups, v17 introduces comprehensive load balancing for the backoffice, allowing content editors to work seamlessly across scaled infrastructure.
- UTC Date Standardization: A long-awaited fix for global teams—system dates are now consistently stored in UTC, eliminating timezone headaches for international deployments.
The Major Shift: A New Backoffice Architecture
For teams migrating from Umbraco 13, the largest breaking change in Umbraco 17 is the complete removal of AngularJS. The backoffice has been rebuilt from the ground up to be more modern, lightweight, and extensible.
The new "Bellissima" backoffice is powered by a modern tech stack consisting of Lit (for standard web components), TypeScript and Vite. While this offers massive performance gains and a better developer experience, it does mean that legacy packages, custom dashboards, and property editors written in AngularJS will no longer work. These elements must be rebuilt using the new Extension API to function in Umbraco 17.
The Status of Umbraco 13 (Previous LTS)
With the arrival of v17, the torch has been passed. The previous LTS version, Umbraco 13, is now entering the sunset phase of its lifecycle.
- Maintenance Mode: Umbraco 13 will soon shift from "Active Development" to "Maintenance Mode," meaning it will stop receiving new features.
- Security Only: Eventually, it will move to a security-only phase before reaching End-of-Life (EOL) in December 2026.
The Takeaway: If you are currently on Umbraco 13, you are safe for now, but the clock has started ticking. Now is the ideal time to budget and plan your upgrade strategy to avoid a rushed migration next year.
One of the best features of modern Umbraco is the upgrade path. The jump from one LTS to the next (v13 to v17) is designed to be as smooth as possible, though it does require developer intervention.
Official Resources
For the technical deep-dive, check out these official resources from Umbraco HQ:
- Umbraco 17 Release Notes – Full breakdown of features and fixes.
- Umbraco Documentation – Technical guides for developers.
- Product Lifecycle – Check the official dates for LTS support.
Need Help Upgrading?
Upgrading a CMS is about more than just clicking "update" - it’s about ensuring your integrations, custom code, and content structures remain intact and optimised for the new version.
At Blue Window, we specialize in Umbraco and whether you are looking to jump from Umbraco 13 to 17, or you are rescuing a legacy site from an older version, our team is ready to assist.
Don't wait until the last minute. Ensure your platform is secure, fast, and supported for the future.