I have both editions. I own the old Don & Co Edition since a long time and recently won the new Huch & Friends edition in a Gipf Tournament.
The playing pieces are exactly the same. The board size is exactly the same.
The three minor changes are: The board outside the playing field is a little bit darker (this is the same for Gipf). The box is nearly twice as big. The game now includes rules in seven instead of six languages (the added Polish).