xep-0450-v0.3.0
Update to XEP-0420 version 0.4.0 and XEP-0434 version 0.5.0: * Replace SCE's old 'content' element by its new 'envelope' element * Replace SCE's old 'payload' element by its new 'content' element * Update SCE's namespace to 'urn:xmpp:sce:1' * Update TM's namespace to 'urn:xmpp:tm:0' * Update namespace to 'urn:xmpp:atm:1'