2021 update: It turns out that the Neumann drive was never installed on the ISS.
Instead, Neumann Space will perform a 1st flight demonstration on a 6U Cubesat in 2022. See a more detailed answer in this answer to Was the Isp = 11,000 seconds Neumann Drive tested on the ISS? Did it work? How well did it perform?
Patrick Neumann told me they had to raise a bunch of cash in order to pay for ride and slot on the Airbus/ESA Bartolomeo module for the ISS. I suspect they weren't able to do it in time and had to find other ways to perform a flight demonstration.
See https://neumannspace.com/the-spirit-mission-is-a-go/ which describes their scheduled first flight on a 6U ...