[tei-council] Monday ticket agenda

James Cummings James.Cummings at oucs.ox.ac.uk
Sun Feb 7 15:28:19 EST 2010

Sebastian Rahtz wrote:
>> As a newbie, I realize I don't know whether, or under what conditions, 
>> changes to P5 that break backward compatibility would be allowed. Is 
>> there a policy on this? I would tend to assume that any changes to P5 
>> should maintain backward compabitility with previous iterations of P5, 
>> while anything that would break compatibility should be moved forward 
>> into the plans for P6. Is that how it works?
> the <soCalled>Birnbaum doctrine</soCalled> states that we should
> never break backward compatibility - except when we really have to.
> It's not forbidden, merely to be taken very seriously.
> There _are_ no plans for P6, it should be noted. Its entirely unclear
> to me what would prompt us to cross that Rubicon.

For others, the 'Birnbaum doctrine' is simply this document here:

On move to P6 it says:

"Council may break backward compatibility in a more substantial and 
comprehensive way (as happened with the transition to P4 to P5) only 
with the transition to a new major version (e.g., P6, but not P5.99999). 
Such transitions should happen only in response to the emergence of new 
technologies (e.g., the transition from SGML to XML) or the development 
of a new architecture that conveys substantial benefit (e.g., the 
development of the new class system). Historically, new major versions 
have emerged approximately every five years."


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