I wanted to see the rules (Id always played that knocking with the same score was a push, not an undercut). The rules given didnt answer the question so I clicked on the Wikipedia button --- and was taken to the developers page which is all ads. Apparently, there is no way to communicate with the developer, which is a VERY BAD THING!
I picked up the middle card of a run. instead of allowing me to change my meld and knock, it threw away an important card and destroyed my hand when I tried to force the game to do the (to me) sensible thing, it threw away the card I needed to win. VERY frustrating. [I think knocking with 6, 4 moves into the game is a winning proposition.]
The nickname "Metalsmith" is taken, because its MINE! about Gin Rummy Pro