System - to determine what version of the System you are using - use ResEdit. Start ResEdit and double-click on the System file. Scroll through the resource file to the STR resource, double-click on it. When the STR resource is opened, scroll until you see the STR with ID=0. Double-click on ID=0 and you will see the version number and date of the system. (If you are new to ResEdit, I suggest that you do this looking around on a backup copy of your program.)