The current problem with Bluetooth printer is that shopify has not updated the SDK with Star and hence the register and printer take 1 second longer to react than over LAN. I spent a week with Star tech support sharing video of outcomes and the like and it was determined to be a shopify problem. I have shared the videos and emails with a Guru but nothing done. Yet. Does not sound like a big deal but when you are busy and line starts forming the extra second per transactions is a big deal. Register and Printer reaction time is just under 1 second through Star App. Through shopify it takes over 2 seconds.