I just tried the Overkill Solar IOS app with my JBD 200a 4S BMS and it's working well. Both the BMS and the app seem happy on this first day of use. I'm coming from a Daly 200a that stopped working, maybe because of the forced app update. The Daly had let me down more than once during the past year, and I was ready to move on to something else. The Overkill Solar does allow for changing the BMS settings and it was free from the IOS app store.