iOS 4
iOS 4 is the fourth major release of the iOS mobile operating system developed by Apple Inc.. Announced on April 9, 2010, and released on June 21 of the same year, iOS 4 signified a pivotal moment in the evolution of Apple's mobile operating systems. It was the first version to carry the "iOS" name following the release of the iPad, and it marked a significant departure from the previous iPhone OS branding.
Notable Features
iOS 4 brought a host of new features and improvements to Apple devices. Some of the key enhancements included:
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Multitasking: For the first time, iOS users could switch between applications without needing to close them entirely. This function was, however, limited by hardware on older devices like the iPhone 3G and the second-generation iPod Touch.
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Folders: Users could now organize their apps into folders on the home screen, significantly improving app management and accessibility.
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Unified Mail Inbox: iOS 4 introduced a unified inbox, allowing users to view emails from multiple accounts in one place.
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iBooks: This application, previously exclusive to the iPad, was introduced to iPhone and iPod Touch, allowing users to read and download books.
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Home Screen Wallpapers: Users could now customize their home screens with wallpapers, although this feature was not available on the iPhone 3G and the second-generation iPod Touch due to hardware constraints.
Device Support
iOS 4 marked a shift in Apple's support for its older hardware. It was the last major iOS release to support the iPhone 3G, and it dropped support entirely for the original iPhone and first-generation iPod Touch. This was the inaugural instance of Apple ceasing device support as part of a major operating system release, setting a precedent for future updates.
Performance and Improvements
While iOS 4 introduced numerous new features, it also included performance improvements and bug fixes. The operating system improved performance on newer devices, like the iPhone 4, which debuted alongside iOS 4. Notable enhancements included better performance in the Calendar app with the introduction of a month view, improved Touch ID reliability, and an automatic high dynamic range (HDR) feature for the iPhone 5s camera.
Legacy
iOS 4 was succeeded by iOS 5, which continued to build on the features introduced in iOS 4. The introduction of iOS 4 and its subsequent updates played an essential role in shaping modern mobile operating systems, laying the groundwork for Apple's later innovations, including the distinct development of iPadOS.