avatar   Ardon  

A reference that names a version gets that version

A canonical reference without a version resolves to whatever is in scope, so as your dependencies change, the same reference can quietly start pointing at another definition. Pinning fixes that by writing the version into the reference: us-core-observation-lab|3.1.1. We explained the why when Simplifier added canonical pinning in release 2026.3.

Forge used to drop that version and take whichever copy it found. A package you pinned on Simplifier could open in Forge and resolve its references somewhere else. Now Forge honours the pin: the reference resolves to exactly that version, or Forge reports it as unresolved. It never quietly falls back to another version.

References without a version behave as before. They still find the FHIR core definitions and your own project files first, and otherwise the highest version your packages provide. When you pick a base profile or an extension, Forge shows the versions available and can write the pin for you. Read more about versions and version pinning.

The Create a new StructureDefinition dialog in Forge, with the US Core Laboratory Result Observation Profile available in versions 6.1.0 and 3.1.1, and the base profile pinned to 3.1.1.

▲ The US Core lab result profile is available in 6.1.0 and 3.1.1: deriving from 3.1.1 writes that version into the base profile.

Two versions of one package, side by side

Pinning to an older version only helps if that version can stay in your project. Dependency trees rarely agree on versions: US Core 9.0.0 alone pulls in the HL7 extensions package at four versions, as we showed when Simplifier started keeping every version in scope in release 2026.5. Until now Forge kept one version of each package.

Forge now installs versions of the same package side by side, whether you add a second version yourself or a dependency brings one in. Your pinned references and your unpinned ones each find what they ask for, and the Dependencies tab shows which versions your project holds. Read more about managing package versions.

The Installed view of the Dependencies tab in Forge, with hl7.fhir.us.core at versions 3.1.1 and 6.1.0, and hl7.fhir.uv.extensions.r4 at versions 1.0.0, 5.2.0 and 5.3.0, each marked side by side.

▲ US Core 3.1.1 and 6.1.0 side by side in one project, and the HL7 extensions package at three versions.

There is nothing to do for existing projects. The first time you open one, Forge restores its packages once, so it can record every version.

Quality Control closer to Simplifier

Quality Control now resolves references to other resources in your project, such as examples, as Simplifier does. Constraints that look at the referenced resource, for instance with resolve(), are now evaluated. Files that Quality Control cannot validate are reported instead of skipped silently.

Please note: Together with Firely .NET Validator 3.5.0, these changes mean the same project can show different findings than before. Run Quality Control after you update and review the results.

Other improvements

  • Firely .NET SDK 6.6.0: Forge now runs on Firely .NET SDK 6.6.0 and Firely .NET Validator 3.5.0.
  • Extensions for another FHIR version: the Add Extension dialog now shows extensions for another FHIR version with the reason they cannot be used, instead of hiding them.
  • Accessibility: screen readers now announce meaningful names for tabs, list rows, element tree items and dialog buttons.

Find the release notes for Forge 2026.3.0 in the documentation. Forge will automatically prompt you to install the latest release, and for new users: this is where Forge can be downloaded from.

Share your feedback

If you have questions or ideas for future developments, do not hesitate to reach out to the Simplifier team. We'd love to hear your feedback.

Other news from Firely
Ardon Toonstra
The Forge 2026.3.0 release brings the two package changes Simplifier introduced this year to Forge: canonical pinning, and more than one version of a package in your project.
Ardon Toonstra
Simplifier now keeps every version of a package that your dependencies bring in and resolves your references predictably across them. This release also redesigns the guides overview and starts retiring DSTU2.
Ardon Toonstra
Earlier this year, we asked the Simplifier community how they use Simplifier, Forge, and Firely Terminal in their day-to-day FHIR work. First of all, thank you to everyone who took the time to participate.
Ardon Toonstra
Simplifier now runs entirely on Firely .NET SDK 6. This release brings a list of rendering improvements for your conformance resources, and consolidates our documentation in one place.
Ardon Toonstra
Forge 2026.2.0 upgrades the profiling engine to .NET 10 and Firely .NET SDK 6.2.1, adds support for the suppression extension, and speeds up loading of complex profiles. Quality Control now runs solely on the current Firely validator, and the Project view's Structure Type filter has been streamlined. Note that .NET 10 may need to be installed by your IT department on managed machines.
Ardon Toonstra
Simplifier.net now hosts country-specific results from the 2026 State of FHIR Survey, letting you explore how HL7 FHIR is being adopted in each participating jurisdiction.
Ardon Toonstra
This release lets you pin canonical references when creating a package, locking each one to the exact version it resolved to so your packages stay reproducible. Simplifier honours the version in a reference when resolving, with two new quality-control rules to help you pin safely. On top of that, the platform has moved to .NET 10, alongside a set of UI improvements and bug fixes.
Ardon Toonstra
The 2026 Simplifier User Survey is now open, and we need your input. Tell us which tools and features drive real value in your FHIR workflow, and where the platform can do better. It only takes a few minutes, and your response shapes what we build next.
Ward Weistra 🔥
Use this new skill to combine Firely Terminal with your AI-driven workflows to give your agent real tools to perform FHIR validation and not just guess.
Ward Weistra 🔥
This latest Forge 2026.1.0 release introduces significant updates, focusing on advanced modeling capabilities, more robust validation, and improved package management to enhance your profiling workflow.
SUBSCRIBE