New WebKit Features in Safari 12.1

There are many improvements and new web platform features in WebKit that are now available with the release of Safari 12.1, included with macOS Mojave 10.14.4 and iOS 12.2. This release delivers web platform features that improve website integration with the operating system, new real-time communication capabilities, more compatible encrypted media support, and features that help developers reduce the need for polyfills. To help websites better integrate with the dark appearance setting in macOS Mojave, WebKit provides the property and media query to allow a webpage to support light and dark color schemes.

Source: webkit.org