I just received my new FP1 battery from the FP shop and was pleased to see that the capacity was increased by ~7.8 %.
Old: 2000 mAh @ 3.7 V = 7.4 Wh
New: 2100 mAh @ 3.8 V = 7.98 Wh
I don’t know when this new battery was introduced and whether it was already in the FP1(U) since I have the First Edition.
Maybe this information is useful to some of you.
Left: Old FP1 first edition battery. Right: new FP1/U replacement battery ordered from FP shop in Feb 2016