PowerCOBOL V3 and later used three files to store the information about a PowerCOBOL project, namely the .prj, .win, and .wcp files.
PowerCOBOL V4 and later combine these 3 files into a single file with the extension .ppj. This simplifies backing up and moving application development.
Check the on-line version of the PowerCOBOL Reference for detailed instructions on converting project files from earlier versions of PowerCOBOL to the 4.0 and later format.
