[idn] req doc: new item proposed

[Marc Blanchet]

Proposed added item in the req document:

[10.5] The protocol should handle with care new revisions of the CCS. 
Undefined codepoints should be not allowed unless a new revision of the 
protocol handle it. Protocol revisions should be tagged.


Marc.

PS. I just wrote a draft (draft-ietf-idn-version-00.txt) to identify some 
ideas on how to handle this.