SuperSU update after 4.4.3 OTA
My 4.4.3 OTA installed just fine this afternoon and I immediately grabbed the latest SuperSU .zip and installed it with TWRP to get re-rooted, but after I told SuperSU to get itself re-installed from Google Play, it wanted to update the binary, and the "normal" method wouldn't work, even after a couple of reboots and retrys.
I don't have TWRP installed on my Nexus 7, instead just using fastboot to boot it when I need it for something, so the technique that finally got the binary updated was to tell SuperSU to use the TWRP update mode, then when it I got the popup saying it was about to reboot to recovery, I plugged in the USB cable and ran:
adb reboot bootloader
fastboot boot openrecovery-twrp-18.104.22.168-flo.img
That worked. As soon as TWRP booted, it installed the script SuperSU had prepared for it, and the binary was indeed updated.
I never had a problem with the "normal" binary update method before. Something new and "helpful" in 4.4.3 I guess.