Safari

Safari is a web browser developed by Apple, based on the WebKit rendering engine and JavaScriptCore scripting runtime. It has been included with macOS since 10.3 Panther, replacing Internet Explorer for Mac as the default web browser, and with iOS since its initial release. It previously supported Windows between versions 3.0 and 5.1.7.

While Safari is an operating system component, on macOS, it can be updated independently of the core operating system. Typically, a major Safari version branch will continue to support the previous two releases of macOS, with these updates distributed via Software Update.

iOS
Safari is built into iOS, and can not be upgraded separately. Starting with iOS 14, the Safari releases closely follow those on macOS. Prior to this, it was typical that Safari on iOS would significantly lag behind macOS releases. However, on occasion, bug fixes would be backported through minor updates to the system WebKit component.

Prior to iOS 7, WebKit's text rendering functionality was used to render UIKit labels, text fields, and text views.

Windows
Safari 3 for Windows was announced by Steve Jobs at the WWDC 2007 keynote as a strategy for "Safari's market share to grow substantially". Apple controversially used its existing install base of iTunes customers on Windows to distribute Safari 3.1 as a "recommended" update in Software Update, selected to be installed by default when the user may believe they are simply installing an iTunes update. The move was criticized by Mozilla CEO John Lilly. Apple later changed Safari's Software Update entry to require the user to manually select it for installation.

Safari for Windows was silently discontinued after version 5.1.7 was released on 2012. No official explanation was given, however it has been assumed to be a combination of its lack of success in gaining more than approximately 4.85% of desktop browser market share, and the introduction of Google Chrome in 2008, at the time being based on WebKit. WebKit nightly builds continued to be released for Windows until 2012.

Safari Technology Preview
Safari Technology Preview is a version of Safari that is regularly updated with recent WebKit development work. It is similar to Google Chrome Dev and Firefox Developer Edition, in that a release is made every few weeks, allowing web developers to test new changes before they appear in the stable release. While the previews are typically stable, they are still not intended for general use.