For release notes, changelog, and HOTween's Visual Editor, head to Download.
If you need help with HOTween, or have any type of feedback, just write it in this thread on Unity forums, so I can see it easily (or if you prefer to open an actual thread, which would be even better, do it and than notify it to me on the linked thread).
Also, you can check (and post) eventual bugs on HOTween's Google Code issues page.
Please consider that I'm only a single person. I will check the forums often, but answers might take some time. Also, I live between Rome (Italy) and Nis (Serbia), thus if you're in a far away time zone I'll be probably sleeping while you post :P
Select the DLL in the Project window or the HOTween GameObject during runtime, and Unity's Inspector will show you which version you're using.
Due to the webplayer security restrictions, this may happen when animating non-sealed properties of other plugins, like NGUI. Switch to HOTweenMicro and everything will work.
Visual Editor projects prior to HOTween v1.3.000 serialized things differently, and you'll need to rename the HOTween.dll, HOTween.dll.mdb, and HOTween.xml files to HOTweenMicro.dll/dll.mdb/xml (don't do it inside Unity).