Since which version has conformance been part of the HL7 standards?

Conformance became an integral part of the HL7 standards starting with version 2.5. This version introduced a more structured approach to conformance statements, which define how specific implementations should adhere to the standards. These conformance statements help clarify the requirements for compliant systems, ensuring they communicate effectively and meet the necessary standards set forth by HL7. This shift marked a significant development in HL7’s efforts to provide guidance and clearer specifications for implementers, allowing for better interoperability and consistency in healthcare data exchange.

Earlier versions, such as 2.1 and 2.3, laid the groundwork for HL7 messaging standards but did not fully incorporate conformance requirements. Version 3.0 further advanced the framework of conformance but could not be considered the initial version that introduced these principles.