just downloaded the patch update for 5.1 from the link given in the forum, and it says 5.0 at every instance where it gives the version, instead of 5.1. ran it anyways to see what would happen (aren't i brave?) and it appears 5.1 installed fine. just gotta update your text i guess.
You may also notice that the desktop shortcut is labled eCabinet Systems 5.0 until you run the program for the first time. Then it gets updated to say eCabinet Systems 5.1.