Reach powered with 3V3?

Has anyone tested whether Reach can run on 3V3 instead of 5V power supply (power supply connected via DF13)?

We’re setting up a Reach for long term (6-month) installation with intermittent pulses of GPS measurements, in this case controlled by a low-power Moteino board for battery longevity. I can use a step-up to bring the Moteino’s output back to 5V, but a so many boards actually operate on 3V3, it would be silly if the board then steps back down…