The meaning of SDScom version numbers

The SDScom version number has three or four numerical parts, separated by a dot - for example, "4.2.0" . Its parts have the following meaning:

• first number (currently 4): Designates the scope of SDScom. It represents the design philosophy and scope of SDScom. In version 4, SDScom aims at transferring documents, while plans for version may shift this to a product-based approach.
• second and third number (e.g. .2.0): Version number of the corresponding EuPhraC / ESCom version: SDScom version 4.2.0 matches EuPhraC version 2.0. All versions of the same major release (SDScom 4.2.x.x) must be downwards compatible, i.e. documents which match a any such SDScom version must validate against any newer version of the same major release. There is one important exception: Any bugs (documented as issues classified with the label "bug") can and should get fixed even if they introduce incompatibilities. Any other changes must become part of the next major release.
• fourth number (if present): maintenance releases between two planned releases of SDScom, e.g. to ditribute urgent bug fixes or match a project schedule.

For example, the next version after 4.2.0 will usually be 4.2.1. If EuPhraC decides to call its next version 3.0, the version would be 4.3.0. If a maintenance release would be necessary before that, it would be 4.2.0.1. (This was discussed also in issue #39) Note that such maintenance release numbers are not mentioned in XmlStandardVersionEnum but a version 4.2.0.1 should be marked as 4.2.0 in SDScom data files; see also issue #52.