After answering your question, I stayed up Friday night testing most of the recent versions of the SDK, and discovered something I was unaware of.
Version 1.2.0.265 does support level changed events correctly.
Version 1.3.0.0 appears to support level changed events correctly.
Version 1.3.0.2, Version 1.3.0.6, and Version 1.3.0.7 do not support level changed events correctly.
Version 1.3.0.11 does support level changed events, but you must setup hail events in order to get level changed events.
Version 1.3.0.23 does not support level changed events, but according to the release note from ControlThink it does support hail events. I was not able to make it work. It could be that something else has to be enabled to get the events working in 1.3.0.23, but I haven't discovered what it is yet, and ControlThink hasn't been much help telling us what we need to change to make hail events and level changed events work in 1.3.0.23.
So my suggerstion to you is to use 1.3.0.11, but you will have to enable the hail events. Since you are using a thermostatV2, Version 1.3.0.11 is probably your best bet since 1.2.0.265 does not support V2 thermostats. But if you want level changed events, remember to enable the hail events, which did not work correctly until 1.3.0.11.