[Standards] Re: Should XEP features with apparent impact be hidden to older clients?

On Wed, 10 Dec 2025 12:04:37 -0500 Stephen Paul Weber <singpolyma@singpolyma.net> wrote:

...

I was wondering whether some features, which have visual impact on messages, should have XML Namespaces (xmlns).

This is already how everything works.

Sorry. I was not aware of it. I changed the title. 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?