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  • Address the remaining points after discussion of last week (See minutes of WT Call 06/02/2019)

Discussion items

1Backward compatibilityThorsten, Petr and the team
  • In the last WT meeting we left open the discussion about backward compatibility.

  • A presentation has been prepared by Petr and Thorsten presented during the meeting: presentation is attached here:
  • Different cases are analysed in the document with the possible combinations of devices and applications evolving to newer version of the model.

The presentation proposes the following behaviour identified as 'sliding window':

  • If all changes from version n to n+1 follow the rules for backward compatibility, respectively only artifacts, which got marked deprecated during former updates already, get removed from the model, then backward compatibility is not an absolute, but a relative characteristic!

Example: Version n+1 will be backward compatibility to version n, but probably not to version n-2

This would be a great improvement, because current way of thinking requires operators to

- update all devices and applications to the latest backward compatible version

- before updating the first application or device to a backward incompatible version

  • In the proposed “sliding window approach”, number of releases and time period of backward compatibility are a compromise between

- programming effort for continued support of deprecated artifacts

- operational effort for roll-out of releases

There is also proposal to change the way we name the releases (no more 1.x, 2.x etc but with month and year of issue indication like 19.2, 19.10 etc. indicating as well the  backward compatibility level with symbol <<.

The topic is quite important but also complex and needs the team to fully understand the scenarios presented (by the real valuable contribution). For this reason, offline discussion is invited, and the topic will be in the agenda of the next WT meeting. 

 2new items for TR-532   A list of the open issues will be distributed to collect the priority input in order to define the order how to address the different topics.

Action items