An ICSP Interface is provided for firmware updates or to program the device with your own code.
For information on a Microchip PIC programmer check out the following link:

pyMCU comes configured by default to operate at 5.0V, if you would like to change pyMCU to work at 3.3V simply desolder J1 5.0V pads and then solder the 3.3V pads.
Please keep in mind that the resistor chosen for the LCD Contrast was done with the idea of working at 5.0V so if you switch to 3.3V you may need to change R3 to a different value resistor.

The LCD pinout works with parallel interface type LCD's with or without backlight.
If for some reason your LCD Contrast is not looking right you can replace resistor at R3 to a value that works for your LCD.
If you change the power setting to 3.3V you will also need to change the resistor to get proper contrast.