Are external pullup resistors required D I/O pins on RN4870/71?
According to datasheet pg 11, there is a pull-up resistance of ~50kΩ. If the pins are naturally pulled high, it must be enabled by default. However, be careful, 50kΩ is a pretty weak pull up, you may need to add in a smaller external resistor if pull up speed is a critical concern (Low pass formed with parasitic capacitance and pull-up resistance, bigger R, larger tau, slower response time).