Just wanted to add my 2-cents. I have 14.2 on all my devices (iphone 10, 11, 12 and the newest apple tv). I woke up on December 16 to discover that these devices were not connecting to wifi. I have a router that's about 4 years old but I have it set to wpa2 with the 5ghz band on 'ac' connections only. I initially thought it was my router so i powered it off/on with no success. I then noticed that my Dell laptops connected to the ac wifi without a problem. To make a long story short, after an hour of playing with different settings, the only way i could get it to connect was changing the 'ac only' selection to 'mixed' (which i didn't want, because it allows slower devices on the 5ghz). I called Apple support and they weren't aware of anything that could have caused this, but they advised me to switch the network to 'ac only' again (which made all my apple devices disconnect immediately). So now, I'm on mixed network again. Maybe an updated router will fix this, but I don't like to be forced to update my router when it seems like an Apple problem. Upgrading to 14.3 did not fix the issue.