The default version of bluez in Raspbian-Jesse is 5.23, which allows bluetooth low energy (BLE) devices to pair and even connect but does not respond to them thereafter! To solve this, one has to install an updated version of bluez. Earlier, I successfully followed this link, which gives the steps to upgrade to bluez-5.37. Bluetooth devices worked after enabling the experimental flag, restarting the bluetooth adapter, and a reboot.
When I tried doing the same thing on another installation of Raspbian now, the system behaves as if it has the old bluez version running. Indeed, I get the perplexing results given below
bluetoothd --version 5.23 bluetoothctl --version 5.37
Is this normal? It looks like inspite of the upgrade, the old bluez version is being actually used -- but I don't know, I'm guessing. How do I remedy this? If you are suggesting removing bluez-5.23, please tell me how to do that. I tried uninstalling bluez from pi, but that removes pi-bluetooth as well. What should I remove and what should I keep, for the BLE devices to work? And how?