avatar   wardweistra  

New blog & whitepaper: From “Must Support” to measurable interoperability with FHIR Obligations

Interoperability isn’t failing because we lack standards. It’s failing in the gap between “FHIR compliant” on paper and systems that actually work together in practice. One of the culprits has been the ambiguity of Must Support: everyone agrees an element “matters,” but nobody encodes what systems are really expected to do with it.

In a new blog post on our website, “From ‘Must Support’ to Measurable Interoperability: Why FHIR Obligations Are a Necessary Next Step,” I explain how FHIR Obligations take that implicit intent and make it explicit, actor-specific, and machine-readable—right inside the ‎⁠StructureDefinition⁠. Instead of hiding behavioral rules in narrative, profile authors can now:

  • Define what behavior is required (e.g. SHALL populate, SHOULD display)
  • Scope it to specific actors (producers, consumers, servers, clients)
  • Add conditions and workflow context via FHIRPath and process links

The blog also clarifies how Obligations and Must Support work together rather than compete. Best practice is that any element with an Obligation is also marked Must Support, keeping profiles both future‑proof (behavioral testing, clearer conformance) and backward‑compatible with tools that don’t yet understand Obligations.

For architects, spec authors, and national programs that need interoperability they can measure instead of just assume, this is a meaningful shift: from narrative expectations to testable behavior.

 

Adding the Obligation extension (1) in Forge to an element that was already marked as Must Support (2)

 

If you want to dive deeper into the rationale, structure, and real‑world adoption, my new whitepaper, “Refining Conformance: An Analysis of the Evolution from Must Support to FHIR Obligations,” is now available as well. The paper walks through:

  • The historical ambiguity of Must Support and its impact on implementations
  • The design and anatomy of the Obligation extension, including the Obligation Codes value set
  • Best practices for combining Obligations with Must Support in real‑world profiles
  • Early adoption by initiatives in Canada, Europe, and beyond

You can read the full blog post here: From “Must Support” to Measurable Interoperability: Why FHIR Obligations Are a Necessary Next Step

And download the accompanying whitepaper here: Refining Conformance: An Analysis of the Evolution from Must Support to FHIR Obligations

Other news from Firely
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.
Ward Weistra 🔥
The latest Simplifier.net release revolves around safety and productivity. While we have implemented new measures behind the scenes to protect accounts, we introduce important innovations for professionals in metadata management, validation and user-friendliness. In this note we explain the improvements and outline what they mean for your FHIR projects.
Ward Weistra 🔥
New on Firely: a deep‑dive blog and whitepaper on how FHIR Obligations sharpen the long‑standing Must Support flag into explicit, actor‑specific, and machine‑readable conformance rules—moving interoperability from narrative intent to testable behavior in real‑world FHIR implementations.
Jay Salvemini
You can now use the new Firely .NET Validator everywhere, simplify your canonical resolving and use the improved project editor. Interested in SSO? Reach out!
Ward Weistra 🔥
January 20, 2025 | Free Online Session. The FHIR Community Process (FCP) is rapidly becoming the global benchmark for quality, transparency, and trust in FHIR Implementation Guides. Learn how to implement it for yourself.
SUBSCRIBE