Hi,
I have a mix of about 20 ESP01 and ESP12F running quietly 
On every boards power supply is between 3.31 and 3.34V, but ESP.getVcc() reads values from 3.39 to 3.49V (except one 3,36V).
(1uF tantalum capacitor near VCC and GND pins, Pin TOUT open, modem active).
Any idea ?
Thx