Question: how to tell difference between hue gen 2 and 3?
Answer: Difference #1: Philips Hue Gen 2 was introduced in 2015, while Hue Gen 3 came in 2016 (800 vs. 600 lumens).
Difference #2: Philips Hue Gen 3 provides more color schemes.
Difference #3: Gen 3 allows you to achieve full dimming while Gen 2 only goes up to RF down to 5%