First draft.
When performing a registration using In-Band Registration (XEP-0077)
Multi-stage IBR must make it possible for a host to ask for further information in response to an initial registration request. It must be usable with clients that only support XEP-0077, though possibly with a degraded user experience.
This use case is identical to one in XEP-0077, except that it allows the Host to request further fields after an initial submission. The examples have been altered to demonstrate one such case. Errors are reported in the same way as XEP-0077, these examples show only a successful case.
In order to determine which fields are required for registration with a host, an entity SHOULD first send an IQ get to the host. The entity SHOULD NOT attempt to guess at the required fields by first sending an IQ set, since the nature of the required data is subject to service provisioning.
Note: The requesting entity MUST provide information for all of the elements (other than <instructions/>) contained in the IQ result.
If the host requires additional information above and beyond the data elements specified in the schema, it SHOULD use Data Forms as described in the Extensibility section of XEP-0077.
When no more fields are requested, the registration is complete.
A given deployment MAY wish to redirect users to another medium (e.g., a website) for further stages of registration, rather than allowing in-band registration. The recommended approach is to include only the <instructions/> element rather than the required fields or a data form in the IQ result, as well as a URL encoded using Out-of-Band Data (XEP-0066)
To support clients that do not implement this specification, the Host SHOULD respond to a query for the registration fields according to what it still needs to know.
Hosts SHOULD expire partial registrations after a reasonable amount of time, after which such a query would return the initial fields again.
No additional concerns over XEP-0077.
This document requires no interaction with the Internet Assigned Numbers Authority (IANA)
This document requires no interaction with the XMPP Registrar