Relaxed version requirement for CodeSystem supplements

Previously, a CodeSystem supplement had to reference a specific version of its base CodeSystem. This made supplements awkward to author and maintain, since they had to be re-pointed every time the base was updated.

Supplements are now no longer required to name a specific base version. This applies whether the supplement is:

• created or updated directly through the API, or
• supplied transiently via the tx-resource parameter to $expand, $validate-code, or $lookup.

The one exception is SNOMED CT supplements that include post-coordinated expressions — these still require a specific base version, because the expressions must be interpreted against a known edition and version.

Wildcard system versions

$expand and $validate-code now accept wildcard patterns in the system-version parameter, so you can pin to a version family without naming an exact release. For example:

system-version=http://terminology.hl7.org/CodeSystem/v3-ActReason|2.x.x

matches any patch release within that minor version.

Alongside this, the check-system-version and force-system-version parameters are now supported on both operations, giving finer control over which CodeSystem version is used during an operation.