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Umbraco 13 end of life: December 14, 2026 and your three options
Jean-Nicolas GauthierLast updated:
Short answer. Umbraco 13 reaches end of life on December 14, 2026, according to Umbraco's Umbraco 13 end-of-life page (checked November 4, 2026). After that date, Umbraco HQ no longer provides security patches, updates or technical support for it. Your site keeps running, but Umbraco strongly advises against using version 13 past that date. Umbraco recommends three options: upgrade to Umbraco 17 LTS, which is supported until November 27, 2028; rebuild on Umbraco 17 LTS or above; or buy Extended Long-Term Support (XLTS) for 6, 12 or 24 months, which can keep version 13 patched until December 14, 2028.
Security update, October 27, 2026. Umbraco released patches for ten vulnerabilities (two high, seven moderate and one low severity) across Umbraco CMS, Umbraco Forms and Umbraco AI. Umbraco 13 is affected: Umbraco CMS 13 up to 13.16.2 has one moderate issue, and Umbraco Forms 13 up to 13.9.11 has one high and one moderate issue. The patched versions are Umbraco CMS 13.16.3, 17.7.2 and 18.2.2, and Umbraco Forms 13.9.12, 17.6.2 and 18.2.2. Umbraco says projects on Umbraco Cloud received an automatic upgrade for CMS and Forms. Umbraco 14, 15 and 16 are already past end of life and will not get a patch.
This guide covers what end of life changes, how to choose between the options, what drives cost over three years, a timeline you can still meet, and a checklist for the move from 13 to 17.
What end of life means for Umbraco 13
Umbraco 13 was released on December 14, 2023 as a long-term support (LTS) version. Umbraco supports LTS versions for three years: 24 months of support followed by 12 months of security fixes only. Umbraco 13 entered that security-only phase on December 14, 2025, and it reaches end of life on December 14, 2026.
End of life means Umbraco HQ stops providing updates and support for the version, including critical security patches. Umbraco says projects will technically keep running after that date, but it strongly advises against running Umbraco 13 past it, since issues may become impossible to resolve.
Umbraco Cloud projects
Projects on Umbraco Cloud follow the same deadline. Umbraco's end-of-service policy for Umbraco 13 on Cloud sets four dates:
- End of life: December 14, 2026.
- XLTS ends: December 14, 2028.
- Projects move to dedicated hosting: December 14, 2028.
- Hosting ends: December 14, 2029.
The .NET 8 date
Umbraco 13 runs on .NET 8, and Microsoft's support for .NET 8 ends on November 10, 2026, a month before Umbraco's own date. Upgrading Umbraco is the way to move to a newer .NET version, because Umbraco's documentation notes that each new major version of Umbraco also means a new .NET version.
Your options
Umbraco recommends three options for Umbraco 13 projects. Staying on Umbraco is often the right answer, and so is buying time with XLTS while you plan properly.
Upgrade to Umbraco 17 LTS
Umbraco 17 is the current LTS version. It was released on November 27, 2025, runs on .NET 10, and Umbraco states it is supported until November 27, 2028. The Umbraco 17 release notes confirm a direct LTS-to-LTS upgrade from 13 to 17, with database migrations applied automatically. Umbraco 18 can only upgrade from version 16.4 or later, so Umbraco 17 is the natural next stop for a version 13 site.
Direct does not mean small. Umbraco calls the jump from 13 to 17 a milestone upgrade, because it includes the new backoffice architecture introduced in Umbraco 14. The Umbraco upgrade documentation lists the points to plan for:
- AngularJS was removed in Umbraco 14. Any custom backoffice extension, property editor or dashboard written in AngularJS must be rebuilt.
- Umbraco 15 changed the internal data format for Block Editors, so a content migration runs during the upgrade. Test it on a copy of production content.
- Every package you use needs a version compatible with Umbraco 17.
- Commercial add-ons can change licensing. In its Umbraco 17 announcement, Umbraco explains that one-off Umbraco Forms licenses keep working on earlier versions but must move to a subscription for use with Umbraco 17 or later.
Rebuild on Umbraco 17 LTS or above
Umbraco's second option is to start fresh on Umbraco 17 LTS or above, which lets you rethink the whole setup. Since moving from 13 to 17 already means rebuilding backoffice customizations, a rebuild can make sense if your editors have outgrown the content model or you plan a headless front end.
Some teams use the same moment to compare other platforms, especially if the organization already licenses another CMS. Our Kentico vs Umbraco comparison is a good starting point if Kentico is on your list. Replatforming is usually the largest project of all. It is worth it when your reasons go beyond the deadline.
Umbraco 13 XLTS
Extended Long-Term Support for Umbraco 13 keeps security patches coming after end of life. According to Umbraco:
- You choose 6, 12 or 24 months of coverage.
- Coverage begins the day after end of life.
- Extensions must be continuous, with no gaps.
- Updates arrive through a secure, private NuGet feed.
- You get security patches only. The feature set stays frozen.
With 24 months, Umbraco 13 stays patched until December 14, 2028. XLTS needs no code changes, which makes it the lowest-effort way to stay secure while you plan. It does not shrink the upgrade work you will face later. It moves that work to a date you choose.
Staying past the date without XLTS
Running Umbraco 13 after December 14, 2026 without XLTS means no security patches. Umbraco's own comparison rates doing nothing as no protection and a high risk of compliance violations. If a short gap is truly unavoidable, apply the last patch, restrict backoffice access to known networks, put a web application firewall in front of the site and set a firm end date.
Decision table
| Your situation | Most likely fit | Watch out for |
|---|---|---|
| Few backoffice customizations, packages already available for Umbraco 17 | Upgrade to Umbraco 17 LTS now | Block Editor content migration on real data |
| Many AngularJS extensions and no budget until 2027 | XLTS for 6 or 12 months, then upgrade | Coverage must start the day after end of life, with no gaps |
| Large, complex site with a long release calendar | XLTS for 24 months while you plan and phase the work | Letting two years pass without starting |
| Content model no longer fits, or a headless move is planned | Rebuild on Umbraco 17 or replatform, possibly with XLTS as a bridge | Content clean-up, URL redirects and bilingual parity |
| Project hosted on Umbraco Cloud | Upgrade, or XLTS with a clear end before December 14, 2028 | The Cloud hosting dates in 2028 and 2029 |
Three-year cost drivers to compare
We do not publish prices. XLTS pricing comes from Umbraco, and project costs depend on your code. These are the drivers that move a three-year total for each option.
| Cost driver | Upgrade to Umbraco 17 | Umbraco 13 XLTS | Rebuild or replatform |
|---|---|---|---|
| Licensing and subscriptions | Umbraco CMS is open source; commercial add-ons such as Forms may move to subscriptions | XLTS fee per coverage period, plus existing add-ons | Same as an upgrade for an Umbraco rebuild; a new vendor license or subscription for a replatform |
| One-time project work | Rebuild AngularJS extensions, update packages, test content migrations | None at first | Full rebuild: content model, templates, integrations and migration |
| Ongoing updates | Regular Umbraco 17 patches and minor releases | Security patches through a private feed | Umbraco 17 releases for a rebuild; the new vendor's release model for a replatform |
| Feature access | New backoffice and current features | Frozen feature set | Current Umbraco features, or those of the new platform |
| Team skills | Developers learn the new backoffice extension model | No change | Training for developers and editors |
| Next deadline | Umbraco 17 support ends November 27, 2028 | The upgrade still has to happen by the end of coverage | Umbraco 17 dates for a rebuild; the new platform's lifecycle for a replatform |
Note the last row. Umbraco 17 support ends about two weeks before 24-month XLTS for Umbraco 13 would. Whatever you pick, plan for your next move within three years, not just this one.
A realistic timeline from today
- Now: if you run Umbraco 13, move to the October 27, 2026 patch releases (CMS 13.16.3 and Forms 13.9.12), or confirm your Umbraco Cloud project received the automatic upgrade.
- Next two weeks: list your packages, custom backoffice code and Block Editor usage. Check which packages already support Umbraco 17.
- By mid-November 2026: decide between upgrading now, XLTS, or a rebuild or replatform with XLTS as a bridge.
- Before December 14, 2026: if you need XLTS, have it in place so coverage starts the day after end of life.
- 2027: run the upgrade or rebuild in phases, testing the content migration on a full copy of production, in French and English.
- By late 2028: plan the next LTS move, since Umbraco 17 support ends November 27, 2028.
Umbraco 13 to 17 upgrade checklist
Use this checklist to plan the jump from 13 to 17. Most of the work comes from the new backoffice introduced in Umbraco 14, so start with your customizations.
How to score it
- Give each item 2 points if it is done, 1 point if it is in progress and 0 if nobody has started it.
- Add up your points and divide the total by the maximum (2 points times the number of items).
- A score above 75% means you can schedule the work. Between 40% and 75%, close the gaps this quarter. Under 40%, start with an assessment before you commit to a date.
Plan the path
- Confirm your exact Umbraco 13 version and apply the latest 13.x patch first (CMS 13.16.3 and Forms 13.9.12 as of October 27, 2026).
- Target Umbraco 17 LTS, not 18: Umbraco 18 only upgrades from 16.4 or later.
- Check that your hosting supports .NET 10, on Umbraco Cloud or your own servers.
- Set a launch date before December 14, 2026, with room for testing, or put XLTS in place first.
Backoffice and code
- List every backoffice customization built with AngularJS. Umbraco 14 removed AngularJS, so each one needs a rebuild.
- Find properties built on Nested Content or Grid Layout and plan their move to Block List or Block Grid.
- Replace macros and partial view macros with partial views or blocks in the rich text editor.
- Replace the legacy Media Picker with the default Media Picker.
- Review custom controllers under /umbraco/api, which the Management API replaced.
- Check that every package and add-on (Forms, Deploy, Workflow, community packages) has an Umbraco 17 version.
Content and data
- Back up the database and media before every test upgrade.
- Plan for the block editor data migration added in Umbraco 15. It runs during the upgrade and can take time on large sites.
- Test the upgrade on a full copy of production content, not a sample.
- Check English and French variants after the migration, field by field, on a sample of pages.
Testing and launch
- Write a test list for forms, search, member login and integrations.
- Train editors on the new backoffice before launch day.
- Run a performance and accessibility check on key templates after the upgrade.
- Freeze content during the final migration and keep a rollback plan.
How a platform assessment helps
Sengo is a bilingual EN/FR team in Canada that works across Umbraco, Kentico, Sitecore, Optimizely, Contentful, Storyblok and Coveo. We have no reason to push you off Umbraco if it still fits. Our free Umbraco assessment reviews your packages, backoffice customizations and content model, then tells you which option fits and what will drive the effort. It is a good next step if your checklist score is under 75%, or if you are not sure how much of your backoffice needs a rebuild.
Sources
- Umbraco: Security advisory, Oct 27, 2026, published October 27, 2026
umbraco.com - Umbraco 13 End-of-Life (EOL), checked November 4, 2026
umbraco.com - Umbraco long-term support and end-of-life, checked November 4, 2026
umbraco.com - Extended Long-Term Support for Umbraco 13, checked November 4, 2026
umbraco.com - Umbraco CMS 17.0.0 release notes, checked October 2026
releases.umbraco.com - Umbraco 17 LTS release announcement, checked October 2026
umbraco.com - Umbraco: find your upgrade path (version 17), checked October 2026
docs.umbraco.com - Umbraco: breaking changes overview, checked October 2026
docs.umbraco.com - .NET and .NET Core official support policy, checked October 2026
dotnet.microsoft.com
Umbraco 13 end of life: common questions
When does Umbraco 13 reach end of life?
On December 14, 2026. Umbraco 13 is a long-term support version released on December 14, 2023, and it has been in its security-only phase since December 14, 2025.
What happens if I keep running Umbraco 13 after December 14, 2026?
The site keeps working, but Umbraco HQ stops providing security patches, updates and technical support for it. Umbraco strongly advises against running version 13 past that date without Extended Long-Term Support (XLTS).
Can I upgrade directly from Umbraco 13 to Umbraco 17?
Yes. The Umbraco 17 release notes confirm a direct LTS-to-LTS upgrade with database migrations applied automatically. Plan for rebuilding any AngularJS backoffice extensions and for the Block Editor content migration added in Umbraco 15.
How long can XLTS keep Umbraco 13 patched?
You choose 6, 12 or 24 months of coverage. It begins the day after end of life, so 24 months keeps Umbraco 13 patched until December 14, 2028. XLTS covers security patches only.
Is Umbraco 13 affected by the October 27, 2026 security advisory?
Yes. Umbraco CMS 13 up to 13.16.2 and Umbraco Forms 13 up to 13.9.11 are affected. The patched versions are CMS 13.16.3 and Forms 13.9.12. Umbraco says projects on Umbraco Cloud received an automatic upgrade for CMS and Forms.
Umbraco 13 reaches end of life. Plan your next step.
Umbraco 13 reaches end of life on December 14, 2026. Get a free assessment: version check, upgrade inventory, upgrade, XLTS or move options and a 3-year cost view.