http://www.langner.com/en/wp-content/uploads/2013/11/To-kill... (36 page PDF)
Langner was the first researcher (outside of those who were involved in its creation) to discover Stuxnet.
> "Whatever the effect of the overpressure attack was, the attackers decided to try something different in 2009. That may have been motivated by the fact that the overpressure attack was lethal just by accident, that it didn’t achieve anything, or – that somebody simply decided to check out something new and fresh."
> "Summing up, the differences between the two Stuxnet variants discussed here are striking. In the newer version, the attackers became less concerned about being detected. It seems a stretch to say that they wanted to be discovered, but they were certainly pushing the envelope and accepting the risk."
> "The dramatic differences between both versions point to changing priorities that will most likely have been accompanied by a change in stakeholders. "
I wonder if that's when the Israelis got involved?
Also, this is shockingly readable for the depth and subject matter!