Previously iPhone OS, Apple's iOS is the company's own mobile operating system developed and originally released on the Apple iPhone and the Apple iPod Touch back in 2007.
Several years later it was renamed to iOS and was extended to support other Apple devices such as the iPad and the Apple TV.
Unlike Google's Android and Microsoft's Windows Phone, Apple does not license iOS to other manufacturers and it is the sole maker and seller of iOS devices.
The first version of the OS was released initially with the first iPhone (the iPhone 2G as it was pet-named by the public due to the lack of 3G connectivity).
The iPhone OS 1.1.1 brings the following changes (list not exhaustive):
The iPhone OS 1.1.3 brings the following changes (list not exhaustive):
The iPhone OS 2.0 was introduced with the iPhone 3G. It also marked the introduction of the Apple AppStore and the support for third-party apps by the iPhone OS.
The iPhone OS 2.2 brings the following changes (list not exhaustive):
The iPhone OS 3.0 was introduced with the iPhone 3GS. It was available as an update both to the iPhone 2G and 3G models.
With the introduction of the first iPad the iPhone OS was renamed to iOS. Version 3.2 debuted on the iPad and represents a separate separate branch of the iOS development, which eventually merged back into the main iOS version channel.
Differences compared to the iPhone (list not exhaustive):
The iOS 4.0 was introduced with the iPhone 4. The iPhone 2G and the iPod Touch (1st gen) were no longer supported and were left out of this update. The iPhone 3G and the iPod Touch (2nd gen) could be updated, but have feature limitations. The iPhone 3GS and the iPod Touch (3rd generation) could be updated and support all features.
What's new (list not exhaustive):
The iOS 4.1 brings the following changes (list not exhaustive):
The iOS 4.2 brings the following changes (list not exhaustive):
The iOS 4.2.1 brings the following changes (list not exhaustive):
The iPhone OS 4.2.5 was introduced only on the CDMA iPhone 4 sold by Verizon. It has an exclusive Personal Hotspot feature, allowing the iPhone to turn into a mobile Wi-Fi hotspot.
The iOS 4.3 was presented along with the iPad 2 and it brings the following changes for the whole family (list not exhaustive):
The iOS 5.0 was introduced with the iPhone 4S.
The iOS 5.0.1 brings the following changes (list not exhaustive):
The iOS 5.1 was introduced along with the iPad 3 and it brings the following changes (list not exhaustive):
iOS 6.x is the current generation of iOS. It was introduced with the iPhone 5, but is also the out-of-the-box OS for the iPod Touch (5th gen), iPad 4 and the iPad Mini.
The iOS 6.1 brings the following changes (list not exhaustive):
A-GPS (Assisted GPS) | A2DP (Advanced Audio Distribution Profile) | AAC (Advanced Audio Coding) | Accelerometer | Airplane mode | Alarm Clock | Alphanumeric | AMOLED display (Active-matrix organic light-emitting diode) | Analog | Android | ANT+ | Antenna | APN (Access Point Name) | Apple iOS | Apple Pay | aptX | Audio jack | Auto-focus | AVRCP (Audio/Video Remote Control Profile)
Bada OS | Band | Bandwidth | Bar | Base Station | BeiDou Navigation Satellite System | Benchmarking | Bit | BlackBerry OS | BlackBerry Playbook OS | Bluetooth | bps (Bits per Second) | Brand | Broadband | Browser | Byte
Calculator | Calendar | Call alerts | Calling Plan | Camera | Capacitive Touchscreen | Car Kit | Carrier | CDMA (Code-Division Multiple Access) | CDMA2000 | Cell | Chipset | cHTML (Compact HyperText Markup Language) | CIF (Common Intermediate Format) | Clamshell | CMOS (Complementary metal-oxidesemiconductor) | Color depth | Concatenated SMS | Connected GPS | Construction | Corning Gorilla Glass | CPU (Central Processing Unit) | Crosstalk | CSTN (Color Super Twisted Nematic) | CTIA | Custom ringtones | CyanogenMod
D-Pad (Direction Pad) | DC-HSDPA (Dual Carrier or Dual Cell High-Speed Downlink Packet Access) | Digital Zoom | Display type | DLNA (Digital Living Network Alliance) | DNSe (Digital Natural Sound engine) | Downlink | DRM (Digital Rights Management) | Dual-band | Dual-Mode | Dual-SIM | DVB-H (Digital Video Broadcasting - Handheld) | Dynamic Memory
EDGE (Enhanced Data for Global Evolution) | EDR (Enhanced Data Rate) | EGPRS | EGSM (Extended GSM) | Email client | EMS (Enhanced Message Service) | eSIM | EV-DO | EV-DV | Exchangeable covers | External Antenna Jack | External Display
FCC (Federal Communications Commission) | Feature Phone | Femtocell | Firefox OS | Firmware | Fixed-focus | Flash Memory | Flight mode | Flip-down phone | FM Radio | FM Transmitter | Form factor | FOTA (Firmware Over-The-Air) | FPS (Frames Per Second) | Frame Error Rate | Frequency | FTP (File Transfer Protocol)
Galileo (Global Navigation Satellite System) | GB (Gigabyte) | Gbps (Gigabits per second) | Geo-tag | GLONASS (Global Navigation Satellite System) | GPRS | GPS (Global Positioning System) | gpsONE | gpsOneXTRA Assistance technology | GPU (Graphics Processing Unit)
H.263 | Half-QWERTY keyboard layout | Handwriting recognition | Haptics | Hot Spot | Hot Swap | HSCSD (High-Speed Circuit Switched Data) | HSDPA (High-Speed Downlink Packet Access) | HSDPA+ (High-Speed Downlink Packet Access Plus) | HSP (Headset Profile) | HSUPA (High-Speed Uplink Packet Access) | HTML (Hypertext Markup Language) | Hz (Hertz)
iDEN (Integrated Digital Enhanced Network) | IMAP (Internet Message Access Protocol) | IMEI (International Mobile Equipment Identity) | IP (Internet Protocol) | IP Ratings | IrDA (Infrared Data Association)
Land line | LCD (Liquid Crystal Display) | LED (Light-Emitting Diode) | Li-Ion (Lithium Ion) | Li-Polymer (Lithium Polymer) | LiMo OS | Linux | Location-Based Services (LBS) | Lock code | Long SMS | Long Term Evolution (LTE) | Loudspeaker
Macro | Maemo OS | mAh | Mass Storage mode | MB (Megabyte) | Mbps (Megabit per second) | MeeGo OS | Megapixel | Memory card slot | Memory effect | Messaging | MHz (Megahertz) | Micro USB | microSD | microSDHC | Microsoft Exchange (Server) | MIDI (Musical Instrument Digital Interface) | MIDP (Mobile Information Device Profile) | Mil-Spec (MIL-STD) | MIMO | Mini-USB | miniSD | MMC | MMCmobile | MMS (Multimedia Messaging Service) | Mobile games | Mobile High-Definition Link (MHL) | Mobile IM (Instant Messaging) | Mobile WiMAX | Mobility DisplayPort (MyDP) | Modem | Monochrome | MP3 (MPEG Layer 3) | MPEG (Motion Picture Experts Group) | MPEG-4 video | Multitouch input method | Music playback time (battery life) | Music Player
Packet Data | Pager | PC Sync | PCS (Personal Communications Service) | PDA (Personal Digital Assistant) | Percentile rank | Phone Book Access (PBA) | Phonebook | PIM (Personal Information Manager/Management) | PIN code (Personal Identification Number) | Pixel | Pixel density (PPI) | Polyphonic ringtones | POP3 (Post Office Protocol) | Port | Predictive text input | PTT (Push-To-Talk) | PUK Code (PIN UnlocK Code) | Push
RAM (Random-Access Memory) | RBDS (Radio Broadcast Data System) | RDS (Radio Data System) | Resistive touchscreen | Resolution | Ringer ID | Ringing profiles | Ringtone | Roaming | ROM (Read-Only Memory) | RS-MMC (Reduced-Size Multi Media Card) | RSA (Rural Service Area) | RSS (Rich Site Summary) | Ruggedized (Rugged)
S60 user interface | SAP (SIM Access Profile) | SAR (Specific absorption rate) | Screen protection | SD (Secure Digital) | Secondary camera | Sensors | Side Keys | SIM | SIM lock | Single-Band | Skin | Slimport | Smart Watch | Smartphone | SMIL | SMS (Short Messaging Service) | SNS (Social network service) | Soft keys | Soft Reset | Speed Dial | Stand-by time (battery life) | Stereo Speakers | Streaming Video | Stylus | Sub-QCIF | SVGA | Symbian | SyncML
Talk time (battery life) | TCP/IP | TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) | TEST | Tethering | Text messaging (texting) | TFD (Thin Film Diode) | TFT (Thin Film Transistor) | Theme | To-Do list | Touchscreen | Trackball | Transflash | Transflective | Tri-band
WAP (Wireless Application protocol) | watchOS | WCDMA(Wideband Code Division Multiple Access) | Wearable Technology | webOS | Wi-Fi | Windows Mobile | Windows Phone OS | Wireless email | WLAN | WMV (Windows Media Video)