Hi all,

After some more discussion in the chat room, I am proposing to remove the ambiguity in XEP-0060 by:
  1. replacing the usage of the 'http://jabber.org/protocol/pubsub' feature with that of 'http://jabber.org/protocol/pubsub#subscribe' (which is a feature that is defined to be REQUIRED in section 10);
  2. add a note to document this change and recommend advertisement of 'http://jabber.org/protocol/pubsub' for compatibility;
  3. with regards to another feature, 'http://jabber.org/protocol/pubsub#publish', to no longer define that as being REQUIRED in section 10, as section 7.1.1 clearly defines it to be optional.
Kind regards,

  Guus

On Fri, Oct 3, 2025 at 5:34 PM Guus der Kinderen <guus.der.kinderen@gmail.com> wrote:
Hi all!

MUST a pubsub service advertise <feature var='http://jabber.org/protocol/pubsub'/> with service discovery 'info' responses?

XEP-0060 shows this being done in examples 8 and 18, but there is no normative text that defines this.

The feature is not listed in its "Feature Summary" section, and is not registered with the Registrar.

There has been a discussion around this in the XSF's Discussion chat room today (logs here: https://logs.xmpp.org/xsf/2025-10-03#2025-10-03-f173fd843da7c3ee ).

There are implementations in the wild that require that feature to be advertised, while other software doesn't advertise it.

Given the conflicting implementations, I believe that it would be good to have normative text be added to XEP-0060 to clarify things. I'm not sure yet what that text should be.

What do you think?

Kind regards,

  Guus