Just last week, I updated my Sony Xperia C5’s OS to Marshmallow 6.0. It’s an old OS, but it’s the newest free update from Sony Xperia, without rooting your phone. Everything seems fine, until I found out that Bluetooth is not working properly after the update.
Once you connect your Xperia to any Bluetooth device, it disconnects automatically after 7 seconds (sometimes 8 seconds). Then if you attempt to reconnect it again, it disconnects again. Too bad for me, I cannot find any solution that works for my device.