I recently bought a used GB-X6900B (module version 6) and a GB-5600B (module version 5; a nice-looking white Kevin Lyons version). Unfortunately, I'm receiving frequent disconnects with both watches from my phone (Moto G5 Plus) where the Bluetooth icon on the watch would simply disappear (i.e. no Link-Loss, the connection is not re-established automatically).
I read about the different module versions and that a module update was only needed for Android 5. On the other hand, I also read about unfixable problems with Casio bluetooth modules when reading about BlueWatcher - unfortunately, the original link is down. Does anybody have any information on this?