* Enhances the security features of the system software
* Improves Bluetooth connection stability
* Improves the hands-free calling quality
* Fixes an issue where the headphones cannot be paired on a Windows computer
* Fixes an issue where, when there are 2 Bluetooth devices connected at the same time, the connected devices repeatedly disconnect and reconnect
* Improves general performance of the headphones
If it was something that really added value to the user they would mention it specifically (like on the 5th and 6th items).
I have a Dell laptop that mentioned such vague "improvements". After updating the firmware I couldn't undervolt anymore. Luckily I was able to downgrade.
I have a pair of WF-1000XM3s and this is painfully true. ANC was brilliant on these until I naively updated, and whoosh - instantly and grossly degraded ANC, to the point I previously almost didn't hear people talking at distance, keyboard chatter, city traffic etc. and now I do, no matter the app settings.
I wanted to upgrade to the in-ear XM4s, but after this? NEVER again Sony. At least for portable audio. I got instead a pair of cheap QCY HT07s (then $28, now ~$20) and got quite surprised with ANC performance on these: easily beats the crap of the XM3s-on-latest-firmware, and gets close to the previous one in audio quality. Which is a lot to say about Sony "updates".
On the Bose 700 headphones there was quite a bit of controversy after many users reported the ANC performance getting worse after an update. This was a few years after the headphones were released, so there were theories of it being intentional degradation to get people to upgrade.
Personally I didn't notice any difference. Bose denied any wrongdoing and seemed to spend real effort on investigating the customer complains.
By the way, Sony wearable products make use of their proprietary NN inference library called Nnabla, with a free helper GUI app Neural Network Console for Windows that can export low-code code into Spresense board codes. It is apparently used across the brand for tiny and transparent features like on-head detection through accelerometers. Not super related, but just so you know...
[0] There is no lossless high quality audio over BT, only a bunch of lossy codecs.
If I want equalization or convolution I apply them upstream shortly after decoding.
I don't think major music listening apps will switch your EQ automatically settings based on your listening device. So either you are doing that manually every time you switch devices, or you set your headphone EQ directly.
In any case, the software around this is not clean, and has lots of room for improvement.
I’ve had to set EQ on Bluetooth speakers themselves that didn’t sound so good out of the box.
Though at that point I rather throw away the speakers and get better ones…