iOS 13.5 speeds up access to the passcode field on devices with Face ID when you are wearing a face mask and introduces the Exposure Notification API to support COVID-19 contact tracing apps from public health authorities. This update also introduces an option to control automatic prominence of video tiles on Group FaceTime calls and includes bug fixes and other improvements.
Face ID and Passcode
Simplified unlock process for devices with Face ID when you are wearing a face mask
Passcode field automatically presented after swiping up from the bottom of the Lock screen when you are wearing a face mask
Also works when authenticating with the App Store, Apple Books, Apple Pay, iTunes, and other apps that support signing in with Face ID
Exposure Notification
Exposure Notification API to support COVID-19 contact tracing apps from public health authorities
FaceTime
Option to control automatic prominence on Group FaceTime calls so video tiles do not change size when a participant speaks
Emergency Services
Option to automatically share health and other essential information from your Medical ID with emergency services when you place an emergency call (US only)
This update also includes bug fixes and other improvements.
Fixes an issue where users may see a black screen when trying to play streaming video from some websites
Addresses an issue in the share sheet where suggestions and actions may not load
Some features may not be available for all regions or on all Apple devices. For information on the security content of Apple software updates, please visit this website: https://support.apple.com/kb/HT201222

Apple security updates - Apple Support
support.apple.com

Apple security updates - Apple Support

This document lists security updates for Apple software.