The software also lands with a number of new features, including:
CarPlay: formerly known as iOS in the Car, which supports iPhone calling, music, maps, and messaging. It also allows users to control certain functions through iOS' in-built voice-activated assistance Siri;
Siri improvements: Including natural-sounding voices for U.K. English, Australian English, Japanese, and Mandarin Chinese. You can also use it in push-to-talk mode by holding the Home button for the duration of your query;
Calendar changes: The list view has returned in month view, and the update has also included country-specific holidays added for many locales;
iTunes Radio updates: The radio feature, first introduced in iOS 7, has been updated with new features, including the ability to buy albums over-the-air from "Now Playing";
Accessibility additions: The "parallax" motion feature option now includes Weather, Messages, and multi-tasking user interface animations;
Camera settings bolstered: Including a setting that allows users to automatically enable HDR mode for iPhone 5s users;
Touch ID improved: The software that controls the biometric reader has been improved to make fingerprint recognition better.
Overall, with its user interface and bug fix improvements, the update is designed above all to resolve some of the initial problems with the software, which some insiders previously reported was rushed in order to land in line with the release of iPhone 5s and 5c smartphones in September.
According to Apple, about 82 percent of all compatible iPhones, iPads, and iPod touch devices are running iOS 7 as of late February, based on App Store data.
As many millions have waited to upgrade until some of the known and well-documented bugs and user interface flaws have been resolved, that figure is expected to rise significantly in the next days.
For those not able to download over-the-air, Windows and Mac users can alternatively connect their compatible iPhones, iPads, and iPod touch devices to iTunes, and upgrade by selecting the "Check for Upgrade" button in their device's summary window.
Or, users can download the software bundle (.IPSW) files from Apple's website for offline installations in the coming hours. (Enterprise users can use Apple's Phobos server for download links.)
In past updates, downloads are often slow at first as millions attempt to upgrade at the same time.
Downloading over a Wi-Fi connection is recommended due to the size of the file, and some users may have to delete content from their devices in order to install.