For what it is worth, yes, others are seeing similar behaviour, so you're definitely not imagining it. This might explain some of what you're seeing:
The SNDS portal migration has gone to production and the JMRP messaging changed with it. The new format started showing up around 11 June. It looks like the "ARF to original message" shift is likely a redaction mechanism. The recipient is now masked: X-HmXmrOriginalRecipient is gone, and the To: line comes back as Undisclosed Recipients <X>. Anything parsing as an email address appears to be similarly redacted now. >From what we can see, what does survive for mapping complaints: * Custom X-headers injected at send time, as long as they aren't shaped like an email address. * The Message-ID, which is preserved, so a lookup against send logs still works. * The envelope sender, though it's buried in the envelope-from comment of the first Received header, making it a bit awkward to parse. For anyone using VERP, it seems the workaround is to avoid reading the bounce address out of the report and instead carry the token in a header using the local part only (e.g. X-msg-ID: b-12345-6789-xyz). That comes back as-is. To echo Paulo, it would be great to hear from any MS folks on the list if this behaviour is the intended new baseline we should all be adapting to. Credit to Olivier Moulene and the Postmastery team for bringing this to my attention. Andrew On Thu, Jun 18, 2026 at 1:47 PM Paulo Azevedo via mailop <[email protected]> wrote: > Hello. > > JMRP seems to be TITSUP ( Totally Incapable To Support Usual Performance ): > > Page https://substrate.office.com/ip-domain-management-snds/SNDS/Jmrp > returns 503 and also all of a sudden all my notifications from JMRP > changed format from ARF to original message, which is causing a bit of an > havoc on my abuse management. > > Anyone else seeing the same behaviour ? > > Microsoft lurkers, hello ? > > Regards, > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop >
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