ISO 8583 · Message types
MTI 0421Reversal advice repeat
Read the four digits
0Version family19874Message classReversal2Functionadvice1Origin indicatorAcquirer repeatReversal messages concern an earlier transaction. Their meaning depends on the original transaction and the connection’s reversal procedure.
What this function tells you
An advice carries information under the connection’s advice procedure. An advice is a distinct function, not another name for a request.
The final digit marks a repeat for the stated origin category. Follow the connection’s duplicate handling rules; do not create an unrelated new transaction when processing a repeated message.
Before acting on the message
Match the original transaction before changing its state. A reversal message is not a general instruction to issue a separate refund or start another payment.
This entry follows the 1987 column of Moov’s listed message types. It does not claim that every network supports this message or that a newer standard uses an identical field layout.
Source scope and interpretation
The prose mentions 2007 where its version table and examples use 2003. This reference uses the explicit example column and does not label it as the 2023 edition.
Some usage descriptions conflict with the digits. For example, the source labels 0320 as a request, while its function digit 2 denotes advice. Several response rows also describe a direction that conflicts with the request exchange. This reference explains the components and does not reuse those usage sentences or assert a universal direction of travel.