Apple IIc (Platinum): Mouse Moved from Slot 4 to Slot 7
When the latest ("platinum") version of the Apple IIc was released, the main circuit board was changed to accommodate the new Memory Expansion Card. The firmware was also changed: the logical location for the mouse was moved from slot 4 (where the memory card image now resides) to slot 7.
This causes problems when customers run the sample BASIC program in Appendix A of the AppleMouse II User's Manual. To make the program work correctly with the newest Apple IIc, change all occurrences of [slot] 4 to [slot] 7.