Hello,
1.6.5 is a real backward version - we just didn't have time to release it earlier as the 1.7.x was our main goal.
1.6.5 and 1.7.x are VST 2.4 compatible so they will not work in applications that support VST 2 or VST 3 and not 2.4. I don't know what is the case about the Wave Editor. If it can run AU please use the Audio Unit versions instead.
Regards,
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Mateusz Wozniak
PSPaudioware.com