I met a problem When my external devices is bluetooth 5.0 I can't connect to my equipment through the Phone or Phone 8.
bluetooth 5.0
It's worth checking to see if your BT 5.0 device is advertising that it supports data length extension, but then doesn't implement it. iOS will connect, then attempt to negotiate, and then wait forever for a reply. Some of the sample Nordic code, for example, advertises this feature but doesn't actually handle the request, and this breaks on iPhone 7 and up. Earlier iPhones will work, as they do not support this feature.
Thank you for your reply.Maybe I didn't speak clearly,I found iPhoneX and iPhone8 bluetooth module is Bluetooth5.0, my equipment is bluetooth 5.0 also.
When I was in the application of scanning equipment ,I could find my device.But when I connected devices from the official document method(CoreBluetooth API), it is failed.At the same time,I found that mobile phone system to the bluetooth Settings will connect my device last a period of time and then disconnect.
When you say 'my equipment', does that mean you manufactured them? Are you in the MFi Program?