Today Apple released watchOS 6.1.2
This appears to be a security update.
Get the latest software updates from Apple
Keeping your software up to date is one of the most important
things you can do to maintain your Apple product's security.
The latest version of watchOS is 6.1.2. Learn how to update
the software on your Apple Watch.
Note that after a software update is installed for iOS, iPadOS,
tvOS, and watchOS, it cannot be downgraded to the previous
watchOS 6.1.2 Apple Watch Series 1 and later 28 Jan 2020
Read more there --> Apple security updates