Siri
Siri was originally released as a stand-alone application for the iOS operating system in February 2010, and at the time, the developers were also intending to release Siri for Android and BlackBerry devices. Two months later, Apple acquired Siri. On October 4, 2011, Apple introduced the iPhone 4S with a beta version of Siri. After the announcement, Apple removed the existing standalone Siri app from App Store. "TechCrunch" wrote that, despite the Siri app's support for iPhone 4, its removal from App Store might also have had a financial aspect for the company, in providing an incentive for customers to upgrade devices. Third-party developer Steven Troughton-Smith, however, managed to port Siri to iPhone 4, though without being able to communicate with Apple's servers. A few days later, Troughton-Smith, working with an anonymous person nicknamed "Chpwn", managed to fully hack Siri, enabling its full functionalities on iPhone 4 and iPod Touch devices. Additionally, developers were also able to successfully create and distribute legal ports of Siri to any device capable of running iOS 5, though a proxy server was required for Apple server interaction.
Over the years, Apple has expanded the line of officially supported products, including newer iPhone models, as well as iPad support in June 2012, iPod Touch support in September 2012, Apple TV support, and the stand-alone Siri Remote, in September 2015, Mac and AirPods support in September 2016, and HomePod support in February 2018.
MacOS Sierra
macOS Sierra has received generally positive reviews. Users and critics have praised its functionality, including the addition of Siri and support for Apple Pay in Safari. Macworld gave it 4.5 stars out of 5. Engadget gave it a rating of 87 out of 100 praising the new features such as Siri integration, Universal Clipboard, and Apple Pay while criticizing the unreliability of Auto Unlock, that "Siri isn't always smart enough" and some of the Messages features are only available on iOS 10. Developers of apps that rely on the PDFKit library built into macOS have complained that radical changes to PDFKit introduced in Sierra are causing instability and potential data corruption.