Express language version identifier

[Hendrix, Thomas E]

Dear all:

I have received some customer input that for long term data retention, any
help at all in documenting the controlling standards of Express schema
instances is  appreciated. It is important to have an audit trail back to
the schema version and language version,  in order to properly interpret the
data. 

It is unknown what data retention processes may emerge, but some will
certainly involve migrating data from one version of a schema to a later
version.  Since ISO gives away schemas but sells documents,  one can imagine
very old data stored with a very old version of a schema as the sole clue as
to the data's interpretation (legal as well as practical ). The language
version identifier and also schema version identifier would provide more
clues.

It seems to me that similar problems arise as we move into more distributed
and dynamic implementations (STEP level 3?).