Updates to Exceptions and BackwardCompatible Sets

[Wil Tan]

What are the WG's expectations on possible updates to the list of exceptions?

I'm not suggesting that we would update it often (or at all) but
*should* the need arise, e.g. to change a character currently
classified as DISALLOWED to CONTEXTO and define a contextual rule for
it, what would the process look like?

The set of code points in Exceptions (2.6 of idna-tables-05) is
immutable, so I presume the only way to update it would be to have a
new document that updates this one.

It seems that the BackwardCompatible set can be used as a more
lightweight method to address this use case, though it appears to be
designed only for incompatible changes to Unicode version after 5.1,
and not for errata in version 5.1 itself.

I don't pretend to have completely read all the relevant drafts, so I
may have completely missed the point. If so, please point me in the
right materials.

=wil