45 CFR § 170.505 - Correspondence.
(a) Correspondence and communication with ONC or the National Coordinator shall be conducted by email, unless otherwise necessary or specified.
(1) Consideration for providing notice beyond email, such as by regular, express, or certified mail, will be based on, but not limited to, whether: The party requests use of correspondence beyond email; the party has responded via email to our communications; we have sufficient information from the party to ensure appropriate delivery of any other method of notice; and the matter involves an alleged violation within ONC's purview under § 170.580 that indicates a serious violation under the ONC Health IT Certification Program with potential consequences of suspension, certification termination, or a certification ban.
(2) The official date of receipt of any email between ONC or the National Coordinator and an applicant for ONC–ACB status, an applicant for ONC–ATL status, an ONC–ACB, an ONC–ATL, health IT developer, or a party to any proceeding under this subpart is the date on which the email was sent.
(b) In circumstances where it is necessary for an applicant for ONC–ACB status, an applicant for ONC–ATL status, an ONC–ACB, an ONC–ATL, health IT developer, or a party to any proceeding under this subpart to correspond or communicate with ONC or the National Coordinator by regular, express, or certified mail, the official date of receipt for all parties will be the date of the delivery confirmation to the address on record.