A new build is up on the beta branch, for Windows and Linux, with Lua and C++ support. This is a full update.
Version 4.4 will be announced June 26th, and this will go on the default branch some time next week.
I was not able to get the new vehicles working in time, and It will have to be added in an update. Version 4.4 will have vehicles disabled. If you need this functionality, stick with version 4.3.
A big thanks for all the people who are helping to test it.