From my experience, the UML 2.0 is more complete (more expressive) so that it allows you to design more detailed (for example the activity and sequence/interaction diagram)
As UML 2.0 is latest version of UML. In this version there are around 13 diagrams are present as compare to 9 in earlier version. But, Lots of companies are still following UML 1.0 version.
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