Version 2.3 adds Operation messages through which a DS sends operational information to a 3DS Server or ACS, on its own or tied to a transaction: for example response time and performance reports, flags on fraudulent ecosystem participants, key and certificate rotation notices and compromised device information. A DS using them sends the OReq, or a numbered series of OReqs in order, over a secure link to the recipient; after a failed TCP/IP connection or TLS handshake it retries at once, and after a second failure it ends the attempt and retries every 60 seconds for up to 24 hours. The recipient validates every OReq (Error Code 203 for an invalid element, 201 for a missing one, with component S or A) and answers once, after the whole series, with an ORes carrying the operation status (01 received, 02 series interrupted, 03 requested action not supported or not taken); the DS validates the ORes the same way. Operation messages are not part of the authentication flow.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.