Sorry, but we have to do this again. The experience I got from working with clients using inspectIT is that everybody always goes for the stable version. Once again today we had somebody using 1.5.x - this version is 2 years old. There is absolutely no reason whatsoever not to take the 1.6.x line.
There are two options:
First: We highly highly decrease the time we call something a stable version (as in 3 month to at the very most 6 month time)
Second: We completely drop the stable/preview thing and just go with a version, like for example Chrome.