Nothing is owed if in fact they are licensed coders. In that term they get paid for coded delivered, not for code to be writen. Just like game companies that do it for say the quake II engine. They pay and they get the code. Its as simple as that.

Now in that same subject if its factual that 1.4.1 is paid in full and nothing has been paid for the next release they have all the right to refuse to release it without payment first. I suspect there is much more to the story we dont know. That could be good or bad depending on who is telling the complete truth.