Hi Randhir : There is an Android App called BLE Checker. You can see if your phone supports BT4 or not.
Please note that BLE = Bluetooth Low Energy = Bluetooth Smart = BT 4.0 and newer.
It needs the right hardware, and new phones coming with Android 4.3 and above should have it.
BUT – the BT implementation under Android 4.3 was rubbish. Android 4.4 was better, and Android 5 seems quite good.
Also note that upgrading the OS version on an OLDER phone does NOT bring BTLE as the hardware is not there.
Best regards, Roger