FpML-AWG Updated Schema Versioning

Hi Andrew,

Here's an extension of an earlier idea for discussion.

FpML vocabularies are promised to be backwards compatible within a series. That is, Any FpML document that is valid in a specific vocabulary will be valid with all later vocabularies in that series.
However, even though FpML documents may not be valid with earlier vocabularies in the series, the meaning of the parts which are understood by the older vocabulary are the same. That is, within a series, applications MAY-IGNORE unknown vocabulary.
Vocabularies can change significantly between series. Between series, it is assumed that MUST-UNDERSTAND changes have been made. Applications MUST at least notify when they encounter unknown vocabulary from another series.

To achieve this, each FpML instance
- MUST identify the series of their vocabulary.
- SHOULD identify the specific version of their vocabulary.

To implement this,
- the series of the vocabulary is identified by namespace.
- the version of the vocabulary is identified by additional information, such as a version attribute.

For example, a schemaVersion attribute, which lists whitespace separated pairs of namespace series URIs and version URIs.
<requestQuote xmlns="http://www.fpml.org/FpML-5-0/pretrade" schemaVersion="http://www.fpml.org/FpML-5-0/pretrade urn:fpml:5-0-2-20080808-WD" ...

OR,
For example, an fpmlVersion attribute
<requestQuote xmlns="http://www.fpml.org/FpML-5-0/pretrade" fpmlVersion="5-0-2-20080808-WD" ...

To allow backwards and forwards compatibility within a series, the schema would specify an attribute fpmlVersion with the pattern:
<xsd:pattern value="5-0-*"/>

I would suggest that series include Major and Minor number, with specific version adding a Micro number, Build date and Status code.

Major = increments for architectural changes
Minor = increments for significant content changes, including breaking backwards compatibility (MUST-UNDERSTAND)
Micro = increments for changes which are backwards compatible (MAY-IGNORE)
Build = the build number or date or date time
Status = draft, recommendation, standard, etc.

Cheers,

Jason Polis
ATS Standards Integration
Jason.Polis@xxxxxxxxxxxxxxxxxx
+44 20 7668 7791
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