Umbraco 17 is a Long-Term Support release built on .NET 10. Its features include backoffice load balancing, consistent UTC handling for system dates, and editing improvements on the modern backoffice introduced in Umbraco 14.
For website owners, the important questions are what these changes offer, how long the version is supported, and which parts of an existing website need attention before adopting it.
Umbraco 17 LTS support explained
Umbraco 17 was released on 27 November 2025. Its published lifecycle gives organisations clear dates for maintenance and future upgrade planning:
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Release date: 27 November 2025.
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Security-only phase begins: 27 November 2027.
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End of life: 27 November 2028.
Long-Term Support provides a longer maintenance window than a standard-term release. Teams still need to apply relevant updates and maintain compatible packages, hosting and application code.
See Umbraco’s official support lifecycle for the current schedule.
The modern backoffice in Umbraco 17
Umbraco 17 is the first LTS release to include the modern backoffice introduced in version 14. Its Web Components and TypeScript architecture replaces the AngularJS foundation used in Umbraco 13.
For editors, this brings changes to navigation and everyday interactions. For developers, it provides a different architecture for building property editors, dashboards and other extensions.
Umbraco 17 also introduces support for running the backoffice across multiple servers. This gives larger installations another option for availability and scaling, with the hosting configuration determining how it operates.
Existing AngularJS backoffice customisations need redevelopment for the modern architecture. Their scope should be understood before an upgrade is scheduled.
Editing and publishing changes in Umbraco 17
Several changes affect how editors manage content:
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UTC system dates: Umbraco 17 stores system dates consistently in UTC. Custom date handling and scheduled publishing should be checked during adoption.
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Tiptap rich-text editing: Tiptap is the default rich-text editor carried forward from earlier releases. It became the sole built-in rich-text editor option in Umbraco 16, so this change will be new to teams moving from version 13.
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Navigation and validation: Deep links, keyboard shortcuts and validation badges help editors reach relevant views and identify content requiring attention.
Include editors in a demonstration using your own content. Custom rich-text tools, publishing routines and extension behaviour deserve particular attention.
What .NET 10 means for Umbraco 17
Umbraco 17 runs on Microsoft .NET 10 LTS. This updates the application platform beneath the CMS and influences hosting requirements, development tools and package compatibility.
For technical teams, adopting the release includes checking that the deployment environment and application dependencies support the new runtime.
Performance should be assessed using the website’s own workloads. Response times, search, integrations and publishing behaviour depend on application code, content and infrastructure as well as the CMS version.
What these changes mean for existing websites
The work involved depends on your starting version and how your website has been extended.
Umbraco supports a direct LTS-to-LTS upgrade from version 13 to 17, including the intervening core database migrations. Custom application code, backoffice extensions and third-party packages still require compatibility checks and, where necessary, development.
An upgrade can retain the public-facing design where the implementation allows it. Changes to the backoffice and legacy editors may still require development and content validation.
For the transition itself, read our Umbraco 13 to 17 upgrade guide.
Which Umbraco 17 changes matter for your website?
The relevance of each feature depends on how your organisation uses the CMS.
A distributed editorial team may benefit from clearer date handling. A large installation may need backoffice load balancing. A website with extensive custom editing tools will need particular attention to extension compatibility and editor training.
Use your existing publishing tasks and technical requirements to assess the release. Our Umbraco 17 upgrade checklist provides a separate preparation checklist for version 13 websites.
Discuss what Umbraco 17 means for your website
Understanding the release is the starting point. Your current version, packages, custom functionality, integrations and hosting determine the work needed to adopt it.
Explore Phases’ Umbraco upgrade services to discuss your existing website and the most suitable upgrade route.
