The latest version V4.1Support for Bluetooth stereo music playback (A2DP)Can connect two phones (one torr two)On the Apple phone can display the battery capacityThe use of noise reduction and echo suppression technology, any noisy environment is still excellent sound qualityLong standby (standby time is about four days)A key to boot pairing , can memory automatically connectvoice command(taking or reject calling by saying yesorno to the Mic)How to Connect the Headphones with Your Cellphone（for the first time):1. Open the Bluetooth function on your cell phone;2. Long press the headphones answer button for 3 seconds. After hearing "power on" , dont release the button, continue to hold the button for 4 seconds.3. After a "beep" sound, when red and blue LED light flash alternately, it is turning into pairing mode.4. Use phone Bluetooth to find a Bluetooth device named "s9i", then select this device to pair.5. After pairing this device, Headphones will give a voice remind "connecting".6. Play music7. Long press the power/answer button, headphones will give a voice remind "Power off".No need to repeat all of above steps the next time to pair, you only need to:1. Open the Bluetooth function on your cell phone;2. Short press the answer/power button, after hearing "power on", release the button, then you will hear "connecting".3 Just play music directly.