CAQH CORE 153 EDI Connectivity Rule (Eligibility & Claim Status Operating Rules)
CAQH CORE 153 EDI Connectivity Rule must be combined when determining the overall CAQH CORE Connectivity requirements. The Part 1 of CAQH CORE 153 EDI Connectivity Rule FAQs is given below.

CAQH CORE solicited input on this topic during the rules-development process from the CORE Technical Work Group members and experts within healthcare and other industries, such as financial services. Based on this input, including the information that other healthcare industry projects, CAQH CORE determined that HTTP/S is an appropriate choice as the baseline standard for delivery of healthcare information.
Yes. Payers may support other versions, but they must support HTTPS 1.1 in order to achieve CORE Certification. The intent of the CAQH CORE 153: Connectivity Rule Version 1.1.0 is to provide a safe harbor that application vendors can develop towards without needing to get detailed information from every potential payer with whom they would like to connect.
No. CAQH CORE decided not to require a format for these data elements for Phase I. However, in Phase II and future phases, CAQH CORE does require a specific format for sending these data elements. Please speak with your CAQH CORE-authorized certification testing vendor on how they will work with you on CORE Certification testing given your organization’s current HTTP format requirements and those used by the certification testing vendor.
When completing CORE Certification testing with a CAQH CORE-authorized testing vendor, the entity should check the NO REVISIONS NEEDED (not applicable) box for the detailed certification testing script(s) that do not apply when using SOAP (e.g., the 403 error messages tested under the Connectivity Test Script #2 because SOAP requires other types of error messages). As with all the Phase I CAQH CORE Test Scripts, if an entity checks NO REVISIONS NEEDED for a Test Script it will need to indicate to the testing vendor, in writing, rationale for why the Test Script does not apply. In this case, the rationale would be that the entity is using SOAP over HTTP/S to transport the X12 transactions.