Hello,
 
we have been using RFD8500 pass 1 year. never had any issue either IOS device connection from APP.
till IOS 10 everything was smooth Connection, Automatically reconnecting without opening Setting page on IOS device when ever APP used to launch.
 
but when we upgraded our IOS devices problem started occurring.
=>RFID never reconnects automatically.
=>whenever App Re- Launch, App never reconnect to RFID automatically, earlier it used to.
=>most of the time it gives Error "Failed to Established Connection".
=>need to open Setting disconnect and Connect several times to  get Sucessfully connected.
=>Every time it appears Connected in Bluetooth Setting, after 3-4 Sec, automatically status changes to Not Connected.
 
Please look in to the matter. this issues started only in IOS11.
 
Thanks