Thank you for reaching out to the community, Sorry to hear that you are experiencing issues.
I can confirm that the Firmware Version 4.3.6 was released on the 6th March.
I would recommend that you try uninstalling and re-installing the Bose Connect app.
If you get the issue again after this then please contact on this thread again.
Liam G - Community Support
Apr 1, 2019
Welcome to the Bose Community Forums. I'm sorry to hear that you're experiencing issues with your QuietComfort 35 II headphones but would love to help suggest some troubleshooting to try and resolve this issue.
Firstly, perform a product reset on your headphones. A guide on how to do this can be found on our website HERE.
Following this, perform a Bluetooth reset on your headphones. This can be done by powering on your headset, then slide and hold the Power switch toward the Bluetooth icon for about 10 seconds until you hear "Bluetooth device list cleared". Then, delete the headphones from your previously connected devices on your source device and attempt pairing again.
Should the issue persist, have you tested connecting the headphones to any alternate source devices to compare results?
We do not currently support the downgrading of firmware for products. Further information relating to this can be found on a post HERE.
I'm sorry to hear you're experiencing issues with your QuietComfort 35 II Headphones. What issues are you exactly experiencing currently with your headphones? You may find a thread HERE helpful.
My issue is about microphone sensitivity rather than hearing background noise --> https://community.bose.com/t5/Headphones-Archive/QC35-Comfort-Wireless-microphone-is-too-sensitive/m...
I have upgraded the firmware anyway but haven't yet tested, fingers-crossed but I'm not optimistic.
Apr 16, 2019
ANC is still not as good as it was before. On top of the ANC I now also have regular drops where the audio stutters, with multiple devices. Range is also worse than before. Already resetted the device, but that doesn't work. Worst of all: BOSE decided to stop the downgrading process (the list is empty on btu.bose.com when you pres a d v up down). SO there is no way for me to go down to an earlier firmware (BOSE trying to be the new Apple?).
These headphones were really pricey, and I was expecting good support from BOSE, but all I ever see is the post to reset your headphones or the post that ANC has not been modified. At least give advanced users the option to downgrade the firmware like before.
Or do we have to force a class action lawsuit by multiple users to persuade BOSE?
Mar 6, 2019
I have been struggling as well, with the new update. The previous one was more stable. When paring multiple devices either the audio drops for some seconds frequently or once you disconnect one of the device the audio goes out all together.
Did a reset and also cleared the bluetooth list on all the devices, but the issue is still there.
Mar 16, 2019
Yeah, here are my top issues since the last update: