Umbraco 13 will reach its end of life on 14 December 2026. It's been in security-only support since December 2025, which means it has not received any bug fixes for the last eight months.
After December there won't be any new patches of any kind, so if a new vulnerability pops up in January 2027 there won't be any support for it.
What end of life means
In software an "end of life" or EOL means that the software is no longer supported by the developers or organization that created it. The software still runs fine and won't shut down automatically or anything, but any new security issues that are identified will no longer be patched.
Being compliant also gets more difficult. There's a chance that your org needs to be software compliant, has cyber insurance or works under a contract that requires supported software - if that's the case an unsupported CMS becomes an issue. This usually happens before a security vulnerability becomes a problem.
As time goes on it will become harder and harder to find technology talent that can support older software. Soon the framework that the outdated Umbraco is running on is going to be out of date as well. Eventually the entire stack is going to be out of date and in need of an upgrade. Upgrading the entire stack is a lot more expensive than just the website.
There are three options
Upgrade to 17. Umbraco 17 is the current Long Term Support (LTS), runs on .NET 10 and is supported into late 2028. Most sites land between $8,000 and $30,000 which is broken down below.
Buy XLTS. Umbraco sells Extended Long-term Support for LTS versions, which keeps security and compliance patches coming after end of life. This is the right call if you cannot get an upgrade funded and scheduled before December. It's best to price that out sooner than later.
Do nothing. This is also an option, not a good one but if you have no other options you can choose to not do anything at all. Especially if the site is being retired anyway down the road. It is not a good plan if the site is not being replaced anytime soon.
13 to 17 is an upgrade
Starting with version 9, Umbraco was officially on .Net Core framework. This means that you can do straight in-place Umbraco upgrades versus having to do a full rebuild. Older versions like 7 to 8 had no supported content upgrade path. Everything from version 9 onward is ASP.NET Core, and 13 to 17 is a sequential, supported upgrade. Your content, document types and templates are all upgradable and part of the path.
What it costs
I price these out by the number of extensions that need to be upgrade instead of the number of pages a site has. A ten thousand page site with a stock backoffice is cheaper to upgrade than a two hundred page site with six custom editors.
No custom backoffice extensions. $8,000 to $12,000. Dependency upgrades, template and model fixes, then regression testing. Mostly testing.
A few custom editors and heavy content. $12,000 to $20,000. This is the most common case. Two or three property editors rebuilt in TypeScript and a set of grid layouts remapped to Block Grid.
Several custom extensions, heavy grid content, live integrations. $20,000 to $30,000 and up. Custom dashboards, custom sections, integrations that need rework, and any external APIs that need to upgrade as well.
These costs don't include any new design changes, new features or anything that wasn't in the existing site already. Those are costs that would get quoted separately.
Can you still make December 2026?
There is still plenty of time to upgrade to Umbraco 17. A site with no custom backoffice extensions and light grid usage is roughly four weeks - that includes setting up staging sites and testing the content migration. A site with several custom editors and heavy grid content is closer to nine weeks.
The work is pretty straight forward, but getting funding, quotes, purchase orders, developer set up, environment set up and hosting options, etc take just as much time as the actually work. The sooner you start on the Umbraco upgrade path the better.
Next steps
- Count your custom property editors and backoffice extensions. That number determines your quote more than your page count does.
- Decide on hosting and set up testing environments complete with the required software for version 17.
- Check whether anything you depend on has no version 17 release.
- Get a quote for XLTS as your fallback. This makes December less scary in case you need to fallback to having extra support.
If you want an opinion on the scope of your project, contact me to start talking about your project. There's more about my Umbraco consulting work on the Umbraco migration page.