Upgrade Unifi AP
File needs to be locala on the network
ssh peter@unifi
upgrade http://192.168.0.16:3002/files/uniti-v4.0.15.bin
upgrade http://192.168.0.16:3002/files/unifi-v3.9.54.bin
Can also be done through unifi app.
Note also that wifi network configuration is done globally and not for each individual AP. Took some time to figure that out after deleting the previous configuration.