The requirements for measure terminology service should align with VSAC's notion of expansion identifiers for a program release, such as "eCQM Update 2019-05-10". Searching to discover what expansion identifiers are available MUST be supported. Value set searching, given an expansion identifier, and returning the value sets associated with that expansion identifier, MUST be supported. This assumes that an expansion identifier such as "eCQM Update 2019-05-10" is applicable to multiple value sets across multiple measures. Given an OID or other identifier for a value set, searching for the set of expansion identifiers must be supported. Given a ValueSet.identifier, the ability to retrieve the ValueSet for a specific expansion identifier is required. The ability to $expand a ValueSet for a specific expansion identifier is required. Note the VSAC approach for assigning logical ids (ValueSet.id) seems to have changed. https://cts.nlm.nih.gov/fhir/ValueSet?_id=2.16.840.1.113883.3.526.3.1240&_format=json for example returns a Bundle with 7 entries with .id: 2.16.840.1.113883.3.526.3.1240-20190315, 2.16.840.1.113883.3.526.3.1240-20170504, etc (i.e., the OID followed by a date, not just the OID and using meta.versionId to indictate different versions).