You will be hard pushed to find any maintained XMPP client that doesn't do this out of the box. So at this point, what does it matter in reality? XMPP has an

You will be hard pushed to find any maintained XMPP client that doesn't do this out of the box. So at this point, what does it matter in reality? XMPP has an annually-updated baseline for compliance: https://xmpp.org/extensions/xep-0443.html https://xmpp.org/extensions/xep-0443.html