This build fixes a security issue recently reported by Unity; more importantly it marks the official shift of the New Game+ mode from its beta branch to the default branch.
New Game+ mode is accessed by completing the game in Book 3, then starting a new game in Book 1 with the information (like gems, character names, and various important events retained). You'll also start with more cash and higher stats, so you can dive straight into exploring the many ways big and small the world has changed.