Android 12 should be here any day now, but being the first Monday of the month, and Android 12 only hitting AOSP today, Google is instead releasing what should be the final Android 11 monthly security patch. All of the currently supported Pixel phones, from the Pixel 3 up through the new Pixel 5a, are all receiving this new Android 11 patch for October.
Currently, we are seeing new 11.0.0 files for Pixel 5a (RD2A.211001.002, RD2A.211001.001), Pixel 5 (RQ3A.211001.001), Pixel 4a 5G (RQ3A.211001.001), Pixel 4a (RQ3A.211001.001), Pixel 4 and Pixel 4 XL (RQ3A.211001.001), Pixel 3a and Pixel 3a XL (RQ3A.211001.001), and Pixel 3 and Pixel 3 XL (RQ3A.211001.001).
Google did not provide a changelog for this update.
Google should begin pushing these updates shortly (Settings>System>Advanced>System update), but if you don’t want to wait for Google and prefer to update manually, you will find each factory image or OTA file at the links below. For instructions on how to flash a factory image, here you go. For instructions on how to flash an OTA .zip file, here you go.