This is one of the last 4.x versions to come, we are preparing for version 5.0 which is due to early next year.
Here is what has changed since 4.5:
+ Improved: Minor interface imporevemnts
+ Added: "Registration key accepted." mesage box
+ Improved: "Run minimized" is now overriden for SCR shortcuts
+ Improved: If no Flash installed, uses Flash v7 player (no more v4)
+ Fixed: Error with Shockwave Flash detection on some systems