The first Apple iPhone is now 10 years old. Over that time it has become a revolutionary piece of hardware. But its gesture-based iPhone OS software -- now called iOS -- has been just as revolutionary.
Here's how Apple's groundbreaking mobile operating system has evolved from iPhone OS 1.0 to iOS 11, set to come out later this year.
For all its fanfare, the first iOS was somewhat limited. There was no App Store yet, so early adopters could only use the simple apps that came preloaded. It was basically an iPod with a phone built in.
Much of the web was still unready for the mobile revolution back in 2007. It's a good thing you could pinch to zoom.
Apple's iPhone OS 2 launched with the iPhone 3G in July 2008. The OS update brought several important new features, including always-on email push, Google Maps Street View and most importantly the App Store.
The third major iteration of the iPhone operating system introduced multimedia messaging (MMS), video recording, spotlight search and voice control.
iPhone OS 3.0 was also the first version with cut, copy and paste functionality.
The release of iOS 4.0 brought with it multitasking, spell check and custom wallpapers.
Apple's new iPhone 4, running iOS 4.0 out of the box, introduced the concept of FaceTime video conferencing. At first, the feature only worked when connected to a Wi-Fi network.
The 2011 launch of iOS 5 brought wireless updates to the iPhone, allowing it to be updated without connecting it to a computer via iTunes. The new iMessage instant messenger feature, meanwhile, allowed the sending and receipt of multimedia content over Wi-Fi.
Another huge improvement in iOS 5 was iCloud, which synced your contacts and other personal data.
Apple gave away the first 5GB of cloud storage for free; 15GB of storage cost $20 per year.
iOS 5 also marked the introduction of Siri, Apple's voice-activated digital assistant. It was only available on the iPhone 4S at first.
The sixth version of iOS, released alongside the iPhone 5 (seen here), brought deep Facebook integration, Passbook, panoramic photos and the ability to make FaceTime calls over your cellular network.
Apple's switch from Google Maps to Apple Maps, which also occurred in iOS 6, was terribly received. The not-ready-for-primetime replacement included numerous graphics bugs and a large number of incorrect and out-of-date business listings.
Apple's iOS 7 brought a total visual refresh to the iPhone with its simple, flat-icon style.
Craig Federighi, Apple's SVP of software engineering, explained that the shadowing and texture effects used on icons in the past was a way to distract from the limitations of the display. "But with a display this precise," says Federighi, "there's nowhere to hide. So we wanted a clear typography."
Beyond the new look, iOS 7 brought a new control and notifications center, AirDrop, CarPlay support and the option to change Siri's gender.
iOS 7 also brought with it Touch ID support. Though only available on the iPhone 5S at the time, being able to authenticate through your fingerprint is now a staple of modern phones.
The eighth major version of iOS kept the flat look of iOS 7 while adding useful new features. The iPhone got cross-platform continuity with Mac and iPad (Handoff), QuickType predictions, family sharing, Wi-Fi calling, time-lapse photos, Notification Center widgets and this handy Battery Usage feature that shows you what's draining your battery.
The iOS 8.1 update introduced Apple Pay for contactless payments via near field communication (NFC) and a dedicated payment chip on the iPhone 6 and later devices.
The service got off to a mixed start, with major retailers Walmart and Best Buy refusing to accept Apple Pay as a result of exclusivity deals with a failed competing service.
The Apple Music subscription streaming service arrived with the iOS 8.4 update, pushed to iPhones and iPads shortly after the 2015 Apple Worldwide Developers Conference.
Apple's iOS 9 introduced a low-power mode, a Night Shift mode for easy reading after dark and mass transit support for Maps. The Notes app also got an update, seen here, that allows you to sketch with your finger.
Apple also added the News app in iOS 9. Similar to the app Flipboard, the news aggregator keeps you informed by constantly refreshing headlines from your favorite news sites, CNET included.
The current iteration of iOS, version 10, introduced a sticker store for the Messages app, predictive emoji, chat bubble animations, facial recognition that bundles your photos together by person, and a Bedtime feature to help you get the perfect night's sleep.
Apple's iOS 10 also includes a new Home app that brings together and manages all your compatible smart home devices.
It's only available in beta right now, but Apple has packed a ton of new features into iOS 11. Control Center can be customized, Live Photos can be edited, Siri can translate certain languages and there's a new one-handed keyboard.
Those who install iOS 11 on an iPad will also get a MacBook-like dock on the bottom of their screens.
Want to learn even more about iOS 11? We've got you covered.
Check out iOS 11's best features for iPhone and iPad and the top 12 tricks iOS 11 will bring to your iPhone and iPad.