The version shipped with BT4Pre is 1.1.1 and the new version is 2.0.1. The difference is bkhive is now a part of samdump2 so dumping the users is now a 1 step process instead of 2. It also fixes some endianness problems. You can get the source code for samdump2 2.0.1 from

I thought you might want to know for BT4.