iPhone17 (iOS26) BLE connection issue (MTU, Primary Service)

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I'm developing an App that works with BLE connection based devices. The BLE connection process, which connects well to the iPhone 16 without any problems, has not worked at all since the iPhone 17. Even when using the same iOS26 version, iPhone 17 is the only one having problems.

Progress is stuck after frame 124 in the entire snoop below. Please check if it is a known problem or if there is a solution.

123 2025-11-04 02:01:39.262000 0.000000 localhost () 7c:c6:b6:91:10:04 () ATT 12 Sent Exchange MTU Response, Server Rx MTU: 232

124 2025-11-04 02:01:39.265000 0.003000 localhost () 7c:c6:b6:91:10:04 () ATT 16 Sent Read By Group Type Request, GATT Primary Service Declaration, Handles: 0x0001..0xffff

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Engineer OP

Apple

16h

Please test with iOS 26.1 and if the issue persists, please file a Bug Report on this

In your bug report we would need some diagnostics logs as well. Please go to https://developer.apple.com/bug-reporting/profiles-and-logs/ and follow the instructions for Bluetooth for iOS to install a logging profile on your device.

Then reproduce the issue, and follow the instructions at the above link to create a sysdiagnose.

And attach that to the bug report as well.

If you have separate sniffer logs that shows the interaction, also do include those.

We would also like to know the peripheral devices you are seeing this issue with. Make/Model and if you know, the BT chipset details (HW/FW versions and manufacturer) would be helpful to track this down.

Once done, please share the Feedback ID here, and @mention me in your response so we can take a look at this right away.

Argun Tekant /  WWDR Engineering / Core Technologies

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