SLO not working after upgrade to IdP v5

[Peter Schober]

Cantor, Scott via users <users at shibboleth.net> [2025-01-31 14:28 CET]:
> I'm all but certain we'll deprecate that and the inbound artifact
> support (not outbound) ahead of 6.0, and those are the main use
> cases for that client right now. The SP isn't going to support the
> reciprocal features in the future, so syncing that up is my
> intention.

Does that affect the "Artifact Spoofing" method offered by the SP?
https://shibboleth.atlassian.net/wiki/spaces/SP3/pages/2065334897/BackDoor
(I don't depend on that currently so just asking.)
Or am I misunderstanding "reciprocal features"?

-peter