On Wed, 10 Dec 2025 at 17:47, Schimon Jehudah <sch@fedora.email> wrote:
So, how is it that older clients *do* display contents of elements with
xmlns that is not supported?
is there a directive in the RFC specifications of the XMPP standard
which recommends to realize only elements of supported xmlns?
The idea of this is that clients send wall-of-text rendered bodies, and naive clients display those, but clients which understand particular extensions then process the rewriting rules within fallback to render a different (cleaner) message.
But this comes down to a complex product choice - if you're faced with a reaction, for example, what should a client show? A single emoji as a message? Unfortunately it's the choice of the sender, rather than the receiver, what the fallback body ends up being - and worse, non-naive clients then edit the fallback body according to whatever the sender dictates.
This was not my idea for this spec at all, but it's where consensus got us.
Dave.