I am on an iPhone X ios 14.3, Apple Watch Series 3 (WatchOS 7.3), and Hero 5 Black. I tried three different Hero firmware (1.5, 2.51, and 2.7), but the watch can't connect to the camera. The only useful feature of the app is the watch capablity which is not working. I understand the developer is too small to update the app every GoPro firmware realease, but I think it should be documented which GoPro firmware is supported before buying this app.
UPDATE: You need to select Conenct to GoPro App on the GoPro itself in order to connect to GoRemo, do not select Bluetooth Device. Worked on GoPro Hero 2.51 firmware. Did not test on the latest release of 2.7. I also noticed issues with connection if I try connecting the GoPro app and the GoRemo app at the same time.