Changes:

Updated Intel and AMD graphics drivers
Initial support for AMD Navi graphics cards
AMD users may need to update to WhateverGreen 1.3.4
Updated audio drivers- established users of Catalina with AppleALC or VoodooHDA should not need to update.
Updated USB drivers- those using Port Limit Removal patch may have to update to new patches for 10.15.1

Install macOS Catalina App has been updated - If you downloaded macOS Catalina from the App Store prior to today, and you want to have the latest version on your backup installer USB, simply log into the Mac App Store and click Download. The updated Install macOS Catalina App can be found in the Applications folder.

The macOS Catalina 10.15.1 update includes updated and additional emoji, support for AirPods Pro, HomeKit Secure Video, HomeKit enabled routers, and new Siri privacy settings, as well as bug fixes and improvements.
Emoji
• Over 70 new or updated emoji, including animals, food, activities, new accessibility emoji, gender neutral emoji, and skin tones selection for couple emoji

AirPods
• Introduces support for AirPods Pro

Home app
• HomeKit Secure Video enables you to privately capture, store, and view encrypted video from your security cameras and features people, animal, and vehicle detection
• HomeKit enabled routers let you control how your HomeKit accessories communicate over the internet or in your home
• Adds support for AirPlay 2-enabled speakers in scenes and automations

Siri
• Privacy settings to control whether or not to help improve Siri and Dictation by allowing Apple to store audio of your Siri and Dictation interactions
• Option to delete your Siri and Dictation history from Siri Settings

This update also includes the following bug fixes and improvements:
• Restores the ability to view file names in the All Photos view in Photos
• Restores the ability to filter by favorites, photos, videos, edited, and keywords in Days view in Photos
• Fixes an issue where Messages would only send a single notification when the option to repeat alerts was enabled
• Resolves an issue that caused Contacts to launch to the previously opened contact instead of the contact list
• Adds a two-finger swipe gesture for back navigation in Apple News
• Resolves issues that may occur in the Music app when displaying playlists inside folders and newly added songs in the Songs list
• Improves reliability of migrating iTunes library databases into the Music, Podcasts, and TV apps
• Fixes an issue where downloaded titles were not visible in the Downloads folder in the TV app

For more detailed information about this update, please visit: https://support.apple.com/kb/HT209149
For detailed information about the security content of this update, please visit: https://support.apple.com/kb/HT201222