Hey, I would like to buy Sony WH-1000XM4 but currently I have smartphone - Xiamomi MI9 that has only Bluetooth 4.
Does it impact the performance or maybe reduce the quality?
Thanks.
You wont be able to extract the full potential of the headphones in Bluetooth mode. The difference between Bluetooth 4 0 -> 5 rather than 4.2 -> 5 will be more significant than this. They will however work as 5 is backwards compatible with all previous versions.