Reviving this thread I started in February because delivery rates continue to decline, and I get this threat from Google any time I check their Dashboard:
"One-click Unsubscribe: Needs work — Ensure one-click unsubscribe is correctly implemented for your subscription messages One-click unsubscribe allows recipients to easily unsubscribe instead of marking your messages as spam"
Having recently implemented "Feedback-ID" (Google's proprietary-but-required Feedback Loop mechanism) at my MTA, all this has done is confirm that 0.05-0.10% of subscribers report messages as spam and would probably rather be unsubscribed but cannot be bothered to figure this out. Having the headers that make Google/Yahoo/Apple/etc ask "Would you like to unsubscribe from this?" when they hit the "Junk" button will most likely resolve the problem.
I'm pretty sure, as below, that we need to implement RFC 8058 headers in order to maintain deliverability to GMail. The only tracker issue I can find related to this is https://gitlab.com/mailman/mailman/-/issues/1099 -- is that the best place to discuss implementation?
--Jered
----- On Feb 5, 2025, at 3:36 AM, Stephen J. Turnbull turnbull@sk.tsukuba.ac.jp wrote: [..]
If we're talking about a new feature, I think the most straightforward approach is to use RFC 8058[1] "one click" URLs. I believe it is already implemented by Gmail and Yahoo, I don't know about Outlook or the open source MUAs. This would require a substantial (but straightforward[2]) addition of code, and of course personalized delivery (I don't know if anyone balks at that any more, though). [..] Footnotes: [1] https://datatracker.ietf.org/doc/html/rfc8058
[2] That is, we'd need to add a new location in Postorius and code to accept POST access to it, encrypt/decrypt functionality to handle an opaque token (to prevent automated denial of service by folks without access to the person's email) or a table of one-time tokens with expiration (same purpose, and expiring so the database doesn't grow infinitely). What we wouldn't need to do is to change any exsting code.