I'd like to know if anyone has developed or intends to develop an Undo command. It doesn't appear in the Quest Help file, nor does it seem to be a feature of the GUI.

I'm asking because research in game design has revealed that many IF fans enjoy if not demand Undo functionality. Rather than having to systematically save a game in case of a needed reload, a player can undo the effects of the last command. In some cases they can undo indefinitely.

Now I realize that RPG-type games do not need undo functionality, since it renders their probabilistic systems useless. But in games that do not employ random processes to determine outcomes, the undo command is very handy indeed.

I agree. I've mentioned this before but unfortunately it's never been included in Quest and, I think, is another reason why Quest games generally get given such a hard time by the rest of the IF community. Every other system supports UNDO, why not Quest?

I've added this to the to-do list for Quest 4.0.

Will Quest 4.0 support games created in earlier versions, specifically 3.53, or will some recoding be necessary?

Yes, Quest 4.0 will support games made in all previous versions of Quest.