XEP and RFC Remarks/RFC 6121: XMPP-IM

Full JIDs in roster requests

Full JIDs in rosters ought to be an error since all presence is bare JID based, however this is not spelled out anywhere in the RFC.

How various servers respond to a roster-set with a full JID.

• Prosody rejects with modify, bad-request.
• M-Link allows it.
• ejabberd allows it.
• Openfire strips the resource and sends a roster push.
• Google Talk returns a result but does not send a roster push.

Denying Presence Subscription Requests Use Case

In a scenario, where multiple clients are online at a single account and the user receives a presence subscription request, this request is broadcasted to all connected clients. However, when the user denies the presence subscription request by responding with a presence unsubscribe stanza, this response is not broadcasted to other connected clients. This means they'll still show the request as unanswered and results in a bad UX. https://xmpp.org/rfcs/rfc6121.html#sub-request-handle