We've enabled SASL2 and XEP-0474: SASL SCRAM Downgrade Protection on http://XMPP.is via https://github.com/unredacted/xmpp.is/commit/ed656a71d112b3a8eb3b54427c164f483cce4b54
This solves one of the most important issues mentioned in our blog post https://unredacted.org/blog/2023/11/what-were-doing-in-response-to-the-jabber-ru-mitm-attack/