Hello,
would you consider adding support for work over standard Bluetooth (non-LE) piconet / scatternet? You don't have to pair BT devices if you use listenUsingInsecureRfcommWithServiceRecord / createInsecureRfcommSocketToServiceRecord and compatibility with older smartphones would be much better (any Android >= 4.0.3 should work). Somebody already created Bluetooth mesh network framework which can be used as lower network layer for any app: https://github.com/Rasum/beddernet