iOS16.1 Updated BLE Connection Intervals from iOS16.0?

[Marie_M]

Hello, When Apple officially released iOS16.0 to users, our custom device that uses a nRF52832 Nordic based BLE chip would no longer hold the connection for more that 90 seconds before disconnecting. We realized that with iOS16.0, Apple changed their requested Connection Intervals and we had to modify them on our product to solve.

However, when we updated to iOS16.1 this month, our original Connection Intervals on our product are working again. Does anyone know what Apple changed for iOS16.1 for the connection intervals? Why does iOS16.1 accept 7.5-15ms intervals when iOS16.0 doesn't? There are no changes to the connection interval requirements on the Apple Design Guidelines as of the last revision Oct26th,2022.

For easy comparison, below are the connection intervals that we used in our product with iOS16.

• [Previously Worked with iOS15 & below] Connection Interval for Product: Min 7.5ms - Max 15ms
  • Does not work with iOS16.0
  • Does work with iOS16.1 & iOS16.1.1
• [Had to Change for iOS16.0, 16.0.1, 16.0.2, 16.0.3] Connection Interval for Product: Min 15ms - Max 30ms

Would really appreciate it if anyone can share more info on the BLE change logs for iOS16.1.

Thanks for the help!