Release 2026.3 is now live. The headline of this release is canonical pinning during package creation, which gives you control over exactly which version of a reference your packages point to. We have also upgraded the platform to .NET 10 and shipped a batch of UI improvements and fixes across Simplifier. As always, reach out if you have any questions.
Pin canonical references during package creation
In FHIR, a canonical reference can leave the version off, in which case it resolves to whatever version happens to be in scope at the time. As your dependencies change, the same reference can quietly start pointing somewhere new, and a package that validated cleanly can later render differently or break. Pinning solves this by writing the exact version into the reference.
When you create a package, you can now opt in to pinning. Simplifier locks each canonical reference to the exact version it resolved to at creation time, following the FHIR community's guidance on pinning. The option lives on the package creation form, so it is there when you want it and out of the way when you do not.
A few related changes come with it:
- Every resource in a newly created package now receives the package version automatically if it did not already have one.
- You can now point a canonical reference at a specific version and have Simplifier honour it. A reference written as
canonical|1.0.0resolves to version 1.0.0 wherever it is used, including when rendering resources in a guide and when resolving canonicals through /resolve. - Two new quality-control rules,
explicit-versionandcanonical-pinning, help you pin safely and catch problems early. You can read how to use them in the pinning documentation.
Under the hood, we refactored the canonical resolvers so the same resolution logic is now used consistently across pinning, validation, snapshot generation and more. That also clears the path for something we are working on next: keeping multiple versions of the same package in scope at once.
Upgraded to .NET 10
Simplifier has moved from .NET 8 to .NET 10. This keeps the platform on a current, supported runtime and sets us up for further performance and security work.
Other improvements
- Guide styles without HL7 trademarks: a new guide style based on the HL7 template, but without the HL7 or FHIR logos and branded colors, for implementers who cannot use HL7 trademarks. Existing styles that include those logos now show a short reminder that you are responsible for following HL7 International's guidelines.
- Clearer package versions: the package tabs now make it easier to tell public and private versions of a package apart.
- Guides open the published version: clicking a guide from the Guides tab now opens the default published version instead of the current work in progress.
- Sorting for releases and projects: the releases tab on a project page now supports pagination and is sorted by release date, and projects on the organization page can be sorted by their last update date.
- Steadier editing: the resource editor no longer creates a new file version while you edit within a session.
- Security maintenance: we reviewed and updated our NuGet and NPM packages to address known vulnerabilities.
In closing
Release 2026.3 puts you in control of the versions your packages depend on, and keeps the platform current with the move to .NET 10. If you have questions or ideas for what we should build next, reach out to the Simplifier team. We would love to hear how pinning works for you.