Umbraco 13 End of Support: What to Do Next

Umbraco 13 reaches end of life on 14 December 2026. After that date Umbraco HQ stops releasing security patches and providing support for it, so you should either upgrade to Umbraco 17, the current long-term support (LTS) release, rebuild on 17, or buy extended support (XLTS) to cover the gap while you do one of those. The site will keep running, but every month it runs unpatched adds risk.

There is a second date to know. Umbraco 13 runs on Microsoft .NET 8, and Microsoft ends support for .NET 8 on 10 November 2026, a month before Umbraco’s own deadline. So by mid-December, both the CMS and the framework underneath it are out of support.

What are the Umbraco 13 support dates?

These are the dates Umbraco publishes on its long-term support and end-of-life page, checked at the time of writing.

Version	Type	Released	Security-only phase from	End of life
Umbraco 13	LTS	14 Dec 2023	14 Dec 2025	14 Dec 2026
Umbraco 17	LTS	27 Nov 2025	27 Nov 2027	27 Nov 2028
Umbraco 18	STS	25 Jun 2026	25 Mar 2027	25 Jun 2027

Umbraco 13 has been in its security-only phase since December 2025, which means bug fixes already stopped. Umbraco 17 runs on .NET 10, which Microsoft supports until November 2028. Short-term support (STS) releases such as 18 have a much shorter life, so for most organisations the sensible target is 17.

What actually stops at end of life?

According to Umbraco, three things end on 14 December 2026:

• Security patches and updates from Umbraco HQ.
• Technical support, including for critical security issues.
• Automatic security patches on Umbraco Cloud.

If your site holds member logins, payment journeys or personal data, running unpatched software is also a governance question. Procurement questionnaires, Cyber Essentials assessments and supplier audits increasingly ask whether your software is still supported. “No” is an awkward answer to give a board.

What are your options?

Option 1: Upgrade to Umbraco 17

You keep your content, URLs and most of your front end, and move the codebase to 17. This is the right choice when the site broadly works and the content model still fits the organisation.

Be clear about the size of the job. Umbraco 14 replaced the old AngularJS backoffice with a new one built on Web Components, and Umbraco’s upgrade notes say this “fundamentally changed” how the backoffice is extended. In practice:

• Custom property editors, dashboards and sections built for 13 need rewriting.
• Packages that used the old package.manifest format need a version built for the new backoffice, or a replacement.
• Rich text fields using TinyMCE are migrated to the TipTap editor in version 16, which can change how some content renders.

A simple site with few customisations can be a short upgrade. A site with a dozen custom editors and abandoned packages is closer to a partial rebuild.

Option 2: Rebuild on Umbraco 17, or on another platform

If the site is five or more years old in design terms, the content model no longer reflects how the organisation works, or the upgrade estimate is approaching the cost of a rebuild, start fresh. A rebuild lets you fix the member journeys, the information architecture and the accessibility at the same time.

This is also the point to ask whether Umbraco is still the right platform. For some organisations it clearly is. Others have simplified and would be better served elsewhere. Our guide to Umbraco or WordPress for a professional body sets out how to decide.

Option 3: Buy XLTS to buy time

Umbraco sells Extended Long-Term Support for LTS versions. For Umbraco 13 it is available in 6, 12 or 24-month periods, starting the day after end of life, with no gaps allowed between extensions. It covers security patches only, delivered through a private package feed, and the feature set is frozen. Umbraco does not publish prices; it describes a predictable per-period cost and asks you to book a call.

XLTS makes sense when you have a contractual obligation to run supported software and cannot finish an upgrade in time. XLTS covers Umbraco itself. Patches for .NET 8 are Microsoft’s responsibility and stop on 10 November 2026, so ask your developer how the hosting environment will be kept secure during the extension.

How to choose: a quick decision rule

• The site works, has few customisations and the content model still fits: upgrade to 17.
• The site has heavy backoffice customisation, or the upgrade quote is more than about half the price of a rebuild: get a rebuild quote before you commit.
• You cannot finish either before 14 December 2026: buy the shortest XLTS term that covers your realistic timeline, and start the project now.

A seven-step upgrade plan

1. Inventory the site. List every package, custom property editor, dashboard, integration and scheduled task, with who built it and whether it is still maintained.
2. Check each package for a version 17 release. Anything without one needs a replacement or custom work. This step usually decides the budget.
3. Audit the content. Remove unused document types, media and pages before you migrate them. Less to move means less to test.
4. Upgrade a copy, not the live site. Work on a full clone with a copy of the database, and upgrade .NET and Umbraco together. Umbraco’s notes say version 18 no longer includes the migrations from 13 to 17, so go to 17 first rather than trying to jump further.
5. Rebuild the custom backoffice pieces for the new extension model, and check how migrated rich text renders on real pages.
6. Test the journeys that matter. Member login, join and renewal forms, search, event booking and any CRM sync, then keyboard and screen-reader checks on the key templates.
7. Plan the cut-over. Freeze content edits for the shortest window you can, redeploy, check redirects and analytics, and keep the old environment available for rollback.

If you need a sense of what a build or rebuild might cost before you speak to anyone, our guide to what a website costs in the UK sets out our published ranges.

What to do this week

Find out which exact version you are running (your developer can confirm it from the project files), who holds the hosting account and when your current support contract ends. Then ask your developer for a written package inventory and an upgrade estimate. If that estimate arrives after the deadline, buy time with XLTS rather than running unsupported.

Where we fit

We run a UK chartered institute’s Umbraco site day to day, as part of our work for membership organisations, and handle Umbraco upgrades, migrations and new builds on the current LTS release. For larger estates we start with a fixed-fee discovery phase that ends in a written upgrade-or-rebuild recommendation you own, and afterwards a care plan keeps the site patched.