Google released the monthly Security patch for the AOSP as usual on the first Monday of the month, i.e., on Jan 6 2020, starting the Decade ON POINT.
The list of Supported Devices include Pixel 2, 3, 3a, 4 and their XL varients. The original Pixel and Pixel XL are not supported as Google discontinued support for them in December 2019.
Essential phone also pushed out the update on Jan 6 as it basically works on pure stock android as well. All the other OEMs will push their updates as per their decisions.
The update is fairly small for all Pixel devices, including Pixel 4 and 4 XL which is surprising as they didn’t receive their December 2019 monthly update as promised, and it was tweeted that the December 2019 and January 2020 would be rolled out together(only for Pixel 4 and 4XL).
The update includes :
1. Fix for notification display in UI for all Pixel phones.
2. Fix for flashlight toggle function for Pixel 4 and 4XL.
3. Fix for devices stuck during boot on Android 10 for all Pixel phones.
4. Fix for wifi connection issues for Pixel 2 and 2XL.
5. Call speaker audio improvement for Pixel 3 and 3XL.
6. Fix for color shifting at lower brightness for Pixel 4 and 4XL
7. Smooth display support for WeChat app for Pixel 4 and 4XL.
8. Fix for wifi crash on certain enterprise APs for all Pixel phones.
9. Various stability fixes for all Pixel devices.
The update also includes Security patches for various components of the devices. There were 4 Kernel Component, 15 Qualcomm ,18 Qualcomm closed-source Components, 1 Google Play System, 3 System, 1 Media Framework and 3 Framework patches which included 1 Critical Severity patch, 32 High Severity patches and 4 Moderate Severity patches.

Another thing that Google started December 2019 was the Feature Drop, which was essentially dropping certain features which appear in the new phones to the older phones to make the features available to larger number of audiences. But this month, there appears to be no such sprinkles of happiness among the patches. Google didn’t announce the frequency of the Feature drop, but fingers crossed…