Umbraco 13 reaches end of life on 14 December 2026.
Umbraco 13 was released as a long-term-support version on 14 December 2023 and entered its security phase on 14 December 2025. Standard security support ends on 14 December 2026.
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What “end of life” changes.
The deadline changes your support position before it changes the visible site. Three practical considerations follow.
01
Standard security fixes end
After end of life, Umbraco no longer supplies standard patches or technical support for version 13. Remaining on it becomes an explicit support decision.
02
Vendor-support status changes
Security reviews, insurance renewals and client questionnaires may ask whether core software is vendor-supported. After the deadline, the answer needs either a migration plan or a defined extended-support position.
03
Package support moves to current versions
Package authors follow supported versions. Planning the move early gives you more options for replacing or adapting integrations.
The closer the deadline gets, the less room there is to test.
The dates are fixed; the effort is estate-specific. Starting earlier leaves more room to inventory packages, test custom backoffice extensions, rehearse content migration and plan editor acceptance without compressing the production move.
Before October
Most contingency
Enough room to compare migration routes, test a copy and plan around business dates.
October
Narrowing window
Still practical for many estates, but package or extension surprises consume contingency quickly.
November
Limited contingency
Assessment and risk reduction remain useful, while a rushed production date may be the wrong objective.
1–14 December
Deadline close
Prioritise a defensible support plan and avoid forcing an under-tested cutover around year-end.
After 14 December
Support decision
Standard support has ended. Upgrade, rebuild, or use XLTS as a defined temporary bridge.
The useful first decision: find out what your upgrade involves. The assessment is included before commitment and takes about a week.
Dates checked 27 August 2026 against Umbraco's lifecycle schedule and its official 13-to-17 migration guidance.
What determines the route from 13 to 17.
Umbraco's guidance describes two practical routes: upgrade the existing solution through the required migrations, or create a fresh Umbraco 17 solution and move the schema and content. The right route depends on the packages, custom code and backoffice extensions in your estate.
The backoffice was rewrittenThe big one
From 14 onwards the editing interface uses a new extension model. Custom property editors, dashboards and backoffice extensions written for 13 need to be checked and may require redevelopment for the new backoffice.
Package dependenciesThe common surprise
Every package needs a v17-compatible release, a replacement, or a decision to absorb or remove its function. The inventory can be checked before delivery is scoped.
.NET versionUsually straightforward
The runtime moves with the CMS. Dependencies and custom code pinned to an older .NET version need to be identified and tested as part of the route.
Content and mediaTest on a copy
Content, media, document types and custom data types need to be tested against the chosen migration route. A real copy reveals assumptions that an inventory alone cannot.
Your editorsPlan the transition
The interface your content team uses every day changes appearance and behaviour. A short training session and planned transition period help the technical upgrade land well with editors.
Start with estate-specific upgrade evidence.
We take a copy of your instance, test the most suitable migration route, and give you a written report in about a week. The assessment is included before commitment and remains yours whichever delivery route you choose.
01
Package inventory, with verdicts
Every package in your solution, its v17 status, and where there is no path — replace, absorb, or drop — with the cost of each.
02
Backoffice customisation audit
Every custom property editor, dashboard and extension, with an honest rewrite estimate against the new backoffice.
03
A migration test on a real copy
We test the likely route on a copy and record the adaptations the estate actually requires.
04
A duration and a shape
Weeks, sequence, and what we would need from your team — enough to plan around, and narrow because it is evidence-based.
Send the repository or a database backup, or give us read access to a non-production environment. If none of that is possible yet, a call and a look at the backoffice gets us most of the way.
Book the assessment →Questions
Could we move to Umbraco 18 instead?
It depends on the estate and the upgrade cadence you want. Umbraco 18 is a standard-term-support release and reaches end of life on 25 June 2027. Umbraco 17 is the current long-term-support release and reaches end of life on 27 November 2028, so it is the default comparison when a longer support runway matters.
What does staying on 13 involve?
The site does not stop running on the deadline. Standard fixes and support end, so the organisation needs an explicit migration, rebuild or extended-support plan rather than treating the current position as unchanged.
Can XLTS buy us more time?
Yes. Umbraco offers extended long-term support for 6, 12 or 24 months. It can provide a defined bridge when the December date is impractical, but it postpones the migration decision rather than removing it.
We are on 13 but heavily customised. Is upgrading still the right call?
Not automatically. A heavily customised estate may favour an upgrade through the required migrations, or a fresh Umbraco 17 solution with selected content and functionality moved across. The assessment compares those routes against the actual estate.
Can you work alongside our existing partner or in-house team?
Yes. They bring knowledge of the solution; we can provide the estate assessment, migration test and delivery capacity needed around it. The assessment stands on its own either way.
How do you price the upgrade itself?
Fixed fee against the scope in the assessment, with the fee attached to milestones you define. If a milestone you named is not met, the fee attached to it is not payable and does not accrue. Because scope is written after we have attempted the work rather than before, the usual source of overrun has already been removed.
Next
Map your upgrade in a week, before deciding whether to proceed.
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