With all respect, versioning is not one of NW‘s strengths😀 In my point of view, Oberon 87 was kind of intermediary version introducing mainly type extensions to Modula-2, semantically still a little close to its ancestor. Oberon 90 can be seen more „grown up“ and more distinguishable from Modula-2. The language refinement went on with Oberon-07. br Jörg