Before 7.0, the rule was quite simple, we couldn't transform LARs between versions, for example, it wasn't possible to export from 6.2 and import it to 7.
In the meantime, the rules have changed. For now, it is possible to import lar files to different portal versions as the logic has been changed to check the entities' model schema version. This indicates that we can e.g. import to 7.1 LARs coming from 7.0 or 7.2.
However, we are comparing a java class level constant that is defined by the different entity models and which values have not been maintained correctly.
SCHEMA_VERSIONs values which are defined in the portlet data handlers are compared by portlets (see e.g. the JournalPortletDataHandler), however only the SCHEMA_VERSION for journal was ever updated. This means that according to this validation almost every portlet LARs are compatible between versions.
The current logic seems wrong, also it's very difficult to maintain.
We want to change this with some meta data level check that would make code maintenance unnecessary.