Be aware on pose files (pz2) the version number appears at the top of the document and again toward the bottom. I believe all other files have it just at the top. If you have a number of files to edit, you may want to download the free Editpad Lite text editor (do a google search for it, I do not have the link). You can then use the search/replace feature to search for all instances of Number 4.02 and replace it with number 4.01 in all open documents (you can open mulitple documents in tabs in Editpad lite).