3100mah 3.8v battery vs 3500mah 3.7v

[dt81]

My main concern is how important is that .1v??? Stock battery is 3.8v where as these 3500mah batteries are at 3.7v. Is that going to cause issues with the phone if I use a 3.7v battery?? I know a few people here have purchased a 3500mah battery, is your battery 3.7v? if so, any issues?