New firmware usually rolls out in waves rather than to everybody all at once, it may take a day or two to get around to you. I’m in the UK and still on 4.5.20_0022 too.
I got mine at least 5 days after people posting received it. Just hang tight. Also, I just go to the camera, settings, firmware. A lot of time I see it there faster than going to the app main section - firmware. Thanks