[Qgis-developer] Project file backward compatibility

[Radim Blazek]

What is the project file (PF) backward compatibility policy?

PF written by a lower major release must be supported? Example:  QGIS
2.0 must support 1.7 PF?

PF written by a lower minor release in the same major line must be
supported? Example:  QGIS 1.8 must support 1.7 PF?

PF must be readable by a lower major release? Example:  QGIS 2.0 must
write PF readable by QGIS 1.7?

PF must be readable by a lower minor release in the same major line?
Example:  QGIS 1.8 must write PF readable by QGIS 1.7?

Is it current master considered to be 2.0 in this context?

I have modified WMS to use extended QgsDataSourceURI but the new
encoded URI would break backward compatibility. I can do conversion
when saving/reading to/from PF but is it necessary?

Radim