Revision 1 is the initially released revision with limited distribution.
The holes along the edge of revision 1 are not staggered as described in Using Pin Headers, and requires that any pin headers must be soldered into the board for use.
Revision 1 does not have the Target Power strap described in Target Current Measurement, instead current can be measured across the Power Supply strap as described in Disconnecting the On-Board Debugger.
Figure 1. PIC18F47K42 Curiosity Nano Curiosity Nano Revision 1