iOS is a mobile operating system, developed by Apple Inc. for iPhone, iPad, and iPod touch. Updates for iOS are released through the iTunes software, and, since iOS 5, via over-the-air software updates. With the announcement of iOS 5.0 on June 6, 2011, a USB connection to iTunes was no longer needed to activate iOS devices; data synchronization can happen automatically and wirelessly through Apple's iCloud service. Major new iOS releases are announced yearly during the Apple Worldwide Developers Conference (WWDC), and are usually released in September of the same year, usually coinciding with the release of new iPhone models. The most recent stable release, iOS 10.2.1, was released on January 23, 2017, and the most recent beta release, iOS 10.3 Beta 5, was released on March 8, 2017.
Contents
Overview
iOS did not have an official name until the official release of the iPhone software development kit (iPhone SDK) on March 6, 2008. Before then, Apple marketing simply stated that iPhone ran a version of Mac OS X made specifically for iPhone. When iOS was introduced, it was named iPhone OS. It was officially renamed iOS on June 7, 2010 with the announcement and introduction of iPad. The introduction of iPad, and the existence of iPod touch, meant the iPhone was no longer the only device to run the mobile operating system. iOS 4 was the first major iOS release that reflected the name change. Apple licensed the "iOS" trademark from Cisco Systems.
Versions
June 2007 saw the official first version release of what eventually became iOS – concurrently with the first iPhone. The final 1.x series release was 1.1.5, released shortly after iPhone OS 2.0.
July 11, 2008 saw the public release of iPhone OS 2.0, with upgrades through version 2.2.1 made available.
iPhone OS 3.0 was officially released on June 17, 2009 for iPhone and iPod touch. iPhone OS 3 had updates until version 3.1.3 (released on February 2, 2010). The first generation iPod touch and iPhone have iPhone OS 3.1.3 as their newest available version. iOS 3.2.x was made specifically for the iPad.
On June 21, 2010, iOS 4.0 (formerly iPhone OS) was released to the public and was made available only to the iPod touch and iPhone. iOS 4.0 was announced to have over 1500 new APIs for developers, and included the highly anticipated multitasking feature. iOS 4.2.1 was the final version available for iPod touch (2nd generation) and iPhone 3G. Many features that were included in iOS 4 were not available for the iPhone 3G or iPod touch (2nd generation), such as multitasking and home screen backgrounds due to hardware limitations. iOS 4.2 is the first version to bring major feature parity to iPhone and iPad. The release of the CDMA iPhone for Verizon Wireless saw a branching of iOS. The 4.2 version sequence continued for the CDMA phone while 4.3 was released for all other products
On June 6, 2011, Apple previewed iOS 5, Apple TV 4.4 beta and the iOS SDK 5 beta along with iCloud beta among other products. iOS 5 introduced various features such as the iMessage service which allows users to send messages between iOS devices, a revamped notification system known as Notification Center, Newsstand subscriptions, Twitter was integrated into iOS 5, the Reminders app was introduced, AirPlay got various enhancements, the iCloud service was introduced and added, and over 200 other new features were added. iOS 5.0 supported all iPad models, iPhone 3GS, iPhone 4 GSM & CDMA, iPhone 4S, and the iPod touch (3rd & 4th generation).
iOS 5 had only three minor software updates, 5.0.1, 5.1, and 5.1.1, which were all provided as OTA and iTunes software updates.
Apple concurrently provides the same version of iOS for the comparable model of iPhone and iPod touch, usually devices released in the same calendar year. iPhone users receive all software updates for free, while iPod touch users paid for the 2.0 and 3.0 major software updates. As of iOS 4.0, Apple no longer charges money for iPod touch updates.
As of October 23, 2011, two versions of iOS were never released. iPhone OS 1.2, which after the first beta was replaced by a 2.0 version number; the second beta was named 2.0 beta 2 instead of 1.2 beta 2. The other was iOS 4.2, replaced with 4.2.1 due to a Wi-Fi bug in 4.2 beta 3, causing Apple to release 2 golden masters (4.2 GM and 4.2.1 GM). One version of iOS was pulled back by Apple after being released. iOS 8.0.1 was pulled back by Apple because cellular service and Touch ID were disabled on iPhone 6 and iPhone 6 Plus.
iPhone OS 1
iPhone OS 1 is the first iteration of Apple's touch-centric mobile operating system. No official name was given on its initial release; Apple marketing literature simply stated the iPhone runs a version of Apple's desktop operating system, OS X. On March 6, 2008, with the release of the iPhone software development kit (iPhone SDK), Apple named it iPhone OS (they went on to rename it "iOS" on June 7, 2010). Support of iPhone OS 1 ended in 2010.
iPhone OS 2
iPhone OS 2, the second major release of iOS, became available on July 11, 2008, with the release of the iPhone 3G. Devices running 1.x are upgradable to this version. This version of the OS introduces the App Store, making third-party applications available to the iPhone and iPod touch. Prior to the public release of iPhone OS 2.0, Apple held a keynote event to announce the iPhone OS Software Development Kit ("SDK") to developers. Support of iPhone OS 2 ended in 2011.
iPhone OS 3
iPhone OS 3 became available with the iPhone 3GS. It was released on June 17, 2009. This release added features such as copy and paste, and MMS. Not all features were available on the original iPhone. Devices running iPhone OS 2.x were upgradeable to this software. The final release supported on the original iPhone and iPod touch is iPhone OS 3.1.3. The iPad was introduced with iOS 3.2. Support of iPhone OS 3 ended in 2012.
iOS 4
iOS 4 was made available to the public for the iPhone and iPod touch on June 21, 2010. This is the first major iOS release to drop support for some devices (original iPhone and iPod touch) and that iPod touch users do not have to pay for.
The iPhone 3G and iPod touch (2nd generation) have limited features, including lack of multitasking capabilities and the ability to set a home screen wallpaper, while the iPhone 4, iPhone 3GS, iPod touch (3rd & 4th generation) have all features enabled, such as multitasking. The iPhone and iPod touch (1st generation) cannot run iOS 4.0 and above.
iOS 4.2.1, released November 22, 2010, added iPad compatibility. It was the initial release on the iPad 2. It also was the last version to support iPhone 3G and iPod touch (2nd generation). iOS 4.2.1 replaced iOS 4.2 due to a Wi-Fi bug in iOS 4.2 beta 3, causing Apple to release 2 golden masters (4.2 GM and 4.2.1 GM). Support of iOS 4 ended in 2013.
iOS 5
iOS 5 was previewed to the public on June 6, 2011. It was released for iPhone 3GS, iPhone 4 (GSM and CDMA), iPhone 4S, iPod touch (3rd & 4th generation), iPad, and iPad 2 on October 12, 2011.
iOS 5.1.1 is the final release supported for the iPad (1st generation) and iPod touch (3rd generation). Support of iOS 5 ended in 2014.
iOS 6
iOS 6 was announced and previewed on June 11, 2012, during Apple Worldwide Developers Conference (WWDC) 2012, and its release was stated as Fall 2012. Following the pattern of prior iOS releases, some older devices were no longer supported, specifically the iPod touch (3rd generation), and the iPad (1st generation). Supported devices include the iPhone 3GS and later; the iPod touch (4th generation) and later; and the iPad 2 and later. iOS 6 has limited support on the iPhone 3GS, iPad 2, and iPod touch (4th generation), such as the fact that it doesn't support Siri.
On September 12, 2012, at San Francisco's Yerba Buena Center for the Arts, among other items unveiled, Apple announced three iOS-related items: the next generation iPhone 5, the redesigned iPod touch (5th generation), and the announcement of the release of iOS 6.0 the following week.
iOS 6 was released to the public on September 19, 2012, through iTunes and over-the-air updates.
iOS 6.1.6 is the final release supported for the iPhone 3GS and iPod touch (4th generation). Support of iOS 6 ended in 2015.
iOS 7
Apple announced iOS 7 on June 10, 2013 at its annual Apple Worldwide Developers Conference (WWDC) event, with release announced for sometime in Fall (Northern Hemisphere) or Spring (Southern Hemisphere) 2013. At their iPhone event on September 10, 2013, Apple announced the full release of iOS 7 for September 18, 2013, while also unveiling two new iPhone models: the iPhone 5C and iPhone 5S. With this release, support was again dropped for older devices, specifically the iPhone 3GS (due to hardware limitations) and the iPod touch (4th generation) (due to performance issues). Supported devices on this release include the iPhone 4 onwards, iPod touch (5th generation), the iPad 2 onwards, and the iPad Mini (1st generation) onwards. iOS 7.1.2 is the final release on the iPhone 4.
iOS 8
Apple announced iOS 8 on June 2, 2014, at its annual Apple Worldwide Developers Conference (WWDC) event, with release announced for sometime in Fall (Northern Hemisphere) or Spring (Southern Hemisphere) 2014. At their iPhone event on September 9, 2014, Apple announced the full release of iOS 8 for September 17, 2014, while also unveiling the iPhone 6 and iPhone 6 Plus. With this release, Apple resumed the cycle of dropping support for older devices. However, instead of dropping support for two devices, they only dropped support for one device, specifically, the iPhone 4. Supported devices on this release include the iPhone 4S onwards, iPod touch (5th generation) onwards, the iPad 2 onwards, and the iPad Mini (1st generation) onwards. iOS 8 has limited support on the iPad 2, iPhone 4S, and the iPod touch (5th generation). iOS 8 was also the first version of iOS to have public beta testing be available, not just to developers. The first ever public beta was iOS 8.3 Public Beta 1. All major updates from this one on will receive public beta releases; minor ones don't usually receive them. The final version of iOS 8 is iOS 8.4.1. This release fixed some bugs present with Apple Music and patched TaiG Jailbreak.
iOS 9
Apple announced iOS 9 on June 8, 2015, at its annual Apple Worldwide Developers Conference (WWDC) event, with public release on September 16, 2015. With this release, Apple did not drop support for any iOS devices, with all devices supporting iOS 8 being eligible for an upgrade. Supported devices on this release include the iPhone 4S onwards, iPod touch (5th generation) onwards, the iPad 2 onwards, and the iPad Mini (1st generation) onwards, making iOS 9 have the most supported devices out of any other iOS release, with 22 devices. The iPad 2 is also the first iOS device to support six major releases of iOS, supporting iOS 4 to 9. This is the greatest number of major iOS releases a single iOS device has supported, surpassing the iPhone 4S which supports five major releases (iOS 5 to 9), and iPod touch (5th generation) supporting four major releases (iOS 6 to 9). However, iOS 9 has limited support on all Apple A5 devices (iPhone 4S, iPad 2, iPad (3rd generation), iPad Mini (1st generation), and iPod touch (5th generation)). iOS 9.3.5 is the final release on the iPhone 4S, iPad 2, iPad (3rd generation), iPod touch (5th generation) and iPad Mini (1st generation).
iOS 10
Apple announced iOS 10 on June 13, 2016, at its annual Apple Worldwide Developers Conference (WWDC) event, with a public release on September 13, 2016. With this release, Apple resumed the cycle of dropping support for older devices, specifically devices using either an A5 or A5X processor: the iPhone 4S, iPad 2, iPad (3rd generation), iPad Mini (1st generation) and iPod touch (5th generation). iOS 10 has limited support on the iPhone 5, iPhone 5C, and iPad (4th generation).
Version history: Apple TV (2nd generation) onwards
Information about new updates to Apple TV (2nd generation) onwards is published on Apple's knowledge base.
iOS 4.1
iOS 4.1 was the first version of iOS available on the Apple TV (2nd generation). It included Apple TV Software 4.0.
iOS 5
On October 23, 2011, Apple TV (2nd generation) received the iOS 5.0 software, with My Photo Stream, AirPlay mirroring (from iPhone 4S & iPad 2), NHL, Wall Street Journal, slideshow themes and Netflix subtitles. Contrary to rumors and code found in iOS 5, the release did not bring support for Bluetooth or apps to the Apple TV (2nd generation).
iOS 6
On September 24, 2012, Apple TV (2nd generation) onwards received the iOS 6.0 software update, with Shared Photo Streams, iTunes account switching, better AirPlay functionality, and Trailers searching, among other smaller improvements.
iOS 7
On September 20, 2013, Apple TV (2nd generation) onwards received the iOS 7.0 software update, with iTunes Radio and AirPlay from iCloud.
iOS 8
On September 18, 2014, the third generation Apple TV received the iOS 8.0 software update, with a redesigned UI, Family Sharing and peer-to-peer AirPlay.
tvOS 9
tvOS 9 is an operating system that is 95% based on iOS 9, with adaptations made for a television interface. It was announced on September 9, 2015, alongside the new iPad Pro and iPhone 6S. Tim Cook took the stage and introduced tvOS saying that it was time for the Apple TV to gain a modern OS with support for apps as they are "the future of TV". It will only be available on the Apple TV (4th generation), released in October 2015. It adds a native SDK to develop apps, and an App Store to distribute them, and support for Siri and universal search across multiple apps.
tvOS 10
On June 13, 2016, Apple SVP of Internet Services Eddy Cue announced at WWDC 2016, the next major version of tvOS, tvOS 10. tvOS 10 brings new functionality such as Siri search enhancements, single sign on for cable subscriptions, a dark mode, and a new Remote application for controlling the Apple TV. tvOS 10 was released on September 13, 2016.
iOS 4
The Alarm feature of the built in Clock app in the iPhone and iPod touch has been plagued by major bugs in all versions of iOS 4. The first bug noticed was the "DST bug" which was first seen when some countries switched to/from daylight saving time from/to standard time in October/November 2010. It caused recurring alarms to start going off an hour too early or late. Apple promised the bug would be fixed in iOS 4.2 but according to some reports it still exists even in iOS 4.3.1.
The second alarm clock bug discovered was the "New Year's Day bug" which showed up on January 1, 2011 and January 1, 2012. It caused non-recurring alarms to never work. However two days after each New Year's Day, on January 3, 2011, they "magically" started working again. This bug was seemingly fixed in iOS 4.3.
iOS 5
Apple confirmed that several battery life bugs were negatively affecting battery life in iOS 5. They attempted to fix these bugs with iOS 5.0.1 and 5.1 but the problem still remained. Finally, these bugs were fixed in iOS 5.1.1.
The launch of the iOS 5 update on October 12, 2011 (including iOS 5.0.1 released on November 10, 2011), led many users to report a major bug causing the device to lose Wi-Fi access. This problem has supposedly been fixed with the release of iOS 5.1.1
Some users of the iPhone 4S and iPad (Wi-Fi + Cellular) reported issues with the SIM card in iOS 5.0, and even though Apple attempted to fix these issues in version 5.0.1 build 9A406 (for iPhone 4S only), they still remained.
Some users of the iPhone 4 and iPhone 4S reported issues with having echo problems during phone call in the initial release of iOS 5, which causes echoes to appear randomly during phone calls made through earbuds. The other party in the call is generally unable to hear the conversation due to this problem. Apple has since released version 5.1.1 in an attempt to fix the problem.
iOS 6
Apple has admitted that there were several bugs in the mapping app on iOS 6, with cities in the wrong location, some places being missed off altogether, some places misnamed and places of interest in the sea. Problems submitted by users have gradually been addressed with daily updates to Maps.
Many users report a problem with Bluetooth audio streaming to a range of compatible devices. The sound cuts out every now and then for no apparent reason. As of October 2012, no solution has been provided by Apple.
Location-based reminders do not work for iPads, even though they were promised to work on cellular enabled devices. It has later been clarified by Apple that only the 4th generation iPad and the iPad Mini 1st generation or later will be able to use this.
In iOS 6.1, users reported problems with cellular connectivity. This was addressed for the iPhone 4S in iOS 6.1.1 which "fixes an issue that could impact cellular performance and reliability for iPhone 4S".
Many iPhone users experienced a bug with the Do Not Disturb feature when the calendar changed from 2012 to 2013. The feature would be left on past the scheduled time set by the user, allowing texts, notifications, and alarm settings to be missed. The bug was caused by a difference in formatting in the ISO calendar system versus the Gregorian calendar system. Apple did not offer a quick software update for the bug, instead saying that the bug would fix itself on January 7, 2013.
Another bug causes issues when iOS devices connect to a Microsoft Exchange server to retrieve email, resulting in message "mailbox server resources are consumed, log growth becomes excessive, memory and CPU use may increase significantly, and server performance is affected". Microsoft have suggested several workarounds, and Apple responded with a KnowledgeBase article describing the cause of the bug and a suggested temporary workaround, promising a fix in the near future, which was then fixed with release of iOS 6.1.2.
On iPhones, another bug found in 6.1 allowing bypassing the lock screen's passcode to temporarily gain full access to the Phone app, by performing a specific sequence of actions on the phone that remained unfixed, with Apple acknowledging the bug and then addressed with release of iOS 6.1.3.
iPhone 5 users experienced dropped calls during the release of iOS 6.1.3 when there was an issue with the audio microphone profile. This also caused issues with many voice-over commands, including Siri, to get different results than expected or to fail easily. Apple fixed this bug with the release of iOS 6.1.4, which updated the audio speaker profile so users would get better results.
Shortly when Apple released iOS 7, users running iOS 6 were said to have problems using FaceTime. Apple later released a support document stating that this was due to an expired device certificate and that devices that support iOS 7 should update to it in order to resolve these issues. Devices that are unable to run iOS 7, such as the fourth-generation iPod touch, should upgrade to iOS 6.1.6.
An attacker can collect or modify data in sessions protected by SSL/TLS protocols. This same bug was also reported on iOS 7.0.4 and iOS 7.0.5 for the iPhone 5C and 5S. For the iPhone 3GS and the iPod touch 4th generation, iOS 6.1.6 was released to fix this issue since iOS 7 is not compatible with these devices (see iOS 7.x).
iOS 7
In iOS 7, users that were running iPhone 4 to iPhone 5, iPad 2nd to 4th generations, first-generation iPad mini, and iPod touch (5th generation) have developed bugs that were formerly retained since iOS 6. One example is the SSL/TLS protocol when the secure transport failed to verify certification authenticity (fixed in iOS 7.0.6). This caused the iPhone 3GS (initially ended with iOS 6.1.3) and the iPod touch 4th generation (initially ended with iOS 6.1.5) to advance one update to iOS 6.1.6.
People are able to bypass the "Enter Passcode" screen. This flaw was discovered within hours of it becoming publicly available. This is only able to be done on iPhone 5 and earlier while the iPhone 5C and iPhone 5S are safe from this bug. This is caused by the ability to use the control center via the lock screen and clicking on the camera or timer buttons. This feature can be turned off in the Settings app. This was fixed in iOS 7.0.2.
Users complained about dizziness and vertigo-like symptoms when using this operating system because of parallax motion effects. In iOS 7.1, a new function in the Settings app named "Reduce Motion" was introduced to reduce the motion of the user interface and disable the parallax effects.
Creating a CardDAV Account contains a bug that needs manual fixing of the CardDAV-Server-URL.
In iOS 7.1, users have reported seeing significant drain on their batteries after installing the new update.
Issues with video-calling and connection errors. This was fixed in iOS 7.0.4. (See iOS 6.x)
Local domain names can no longer be resolved in Safari. This breaks short names on the local network, e.g. 'nas' for nas.<ourdomain>.
Users have reported various crashes of the home screen, the core service that renders the home screen icons, Notification Center, Control Center, Siri and the lockscreen. This was fixed in iOS 7.1.
Secure transport failed to validate the authenticity of connection. This issue was addressed by restoring missing validation steps. This may cause an attacker with a privileged network position to capture or modify data in sessions protected by SSL/TLS. This issue was addressed by the release of iOS 7.0.6.
iPhone 4S users report experiencing problems with the battery indicator; the indicator will freeze at the same value until the iPhone is restarted again.
In iOS 7.1, Touch ID was not functioning on the iPhone 5S. The problem cannot be resolved by turning Touch ID on and off in the "Fingerprint and Passcode" menu, restarting, resetting, or restoring the device using iTunes. This problem was similar to the iOS 8.0.1 release, which crippled iPhone 6 and iPhone 6 Plus of both cellular and Touch ID. This was fixed in iOS 7.1.1.
iOS 8
Shortly after the release of iOS 8, Apple released a statement pointing out that a bug had been found in the operating system which prevented HealthKit-compatible apps from being released alongside iOS 8. Apps already released that included Healthkit functionality were withdrawn from the App Store. iOS 8.0.1/8.0.2 included a fix for this issue.
iPhone 6 and iPhone 6 Plus users who updated to iOS 8.0.1 wirelessly had cellular service and Touch ID disabled due to a software issue. Over-the-Air downloads of iOS 8.0.1 were stopped within an hour of the release of the software, but many early adopters had been affected. These issues were fixed with the release of iOS 8.0.2 a day later.
Users who updated phones with Touch ID enabled to iOS 8.3 found out that they could not use Touch ID to make App Store purchases. A workaround has been devised by users to repair this issue.
Many users of older generation devices such as the iPhone 4s and the iPad 2 reported performance issues with iOS 8. Apple has since released iOS 8.1.1 in attempt to fix the problem.
Several issues with the new Keyboard API in iOS 8 were reported, including problems with custom keyboards crashing or not appearing, or being replaced with the default keyboard. Apple has since released iOS 8.3 in attempt to fix the problem.
When a specific set of Arabic, Unicode, and English characters are sent through iMessage to an iOS device running iOS 8.0 or later, it causes the device to crash. This bug was discovered by a reddit user in May 2015. Apple has since released a software update (iOS 8.4) to fix this issue.
iOS 9
Many users of all generation devices experience some issues with Game Center loading times causes long freezes in apps that require Game Center logins. This was fixed in iOS 9.1.
Many users who own the iPhone SE have experienced various issues relating to phone calls via Bluetooth connectivity. The quality of incoming calls via Bluetooth devices was reported to be very low. This issue was fixed in the iOS 9.3.2 update.