> What has Apple opened up along the way? A few highlights: iPhone OS 2 — Native apps. iPhone OS 3 — Apps can now connect to external accessories through ser

> What has Apple opened up along the way? A few highlights: iPhone OS 2 — Native apps. iPhone OS 3 — Apps can now connect to external accessories through serial I/O or bluetooth. Apple also began permitting turn-by-turn navigation and push notifications. Apps can now access music library. Lots of new APIs. iOS 4 — Apps can now perform limited tasks in the background with multitasking. Lots of new APIs. iOS 7 — Multitasking is liberated further. Apps can even send audio streams to other apps. Apps can also run JavaScript directly, allowing app scripting for the first time. Lots of new APIs. iOS 8 — Developers can now create and sell third-party keyboards. Apps can now use Touch ID for authentication; have deeper access to camera exposure settings; register extensions for sharing and notification centre. Lots of new APIs. iOS 10 — New APIs let VoIP apps do stuff that used to be exclusive to the native dialler. Some apps can now hook into Siri. Lots of new APIs. More recently, Apple has relaxed its stance on apps executing (interpreted) code that is downloaded from the internet.