Version 4.0 had a lot of under the hood changes, which unfortunately introduced some bugs. Hopefully most of them have been taken care of with this update.
There are also a few new features: different blend modes and a global moviesource drop zone.
Read the list of updates on the VPT page.
The image is taken from a project Amanda Steggell is doing for the theatre company Verk, where she is using the new blend mode feature for her beautiful emoticons video design.