I would like to point out a simple point.
Where there is compatibility break (like replace the dll doesn't anymore work with the old javascript) the file version should be changed.
Today build 4.0.0.0 FileSize: 233,472 bytes
While few weeks ago the same version was 4.0.0.0 and FileSize: 196,608 bytes.
Between both version all javascripts or almost have changed.
New API sound very nice, gonna dig into that deeper :-)