From the start Apple did not allow third-party software on iOS, but in 2008 they had released an SDK for it, and later that year Apple App Store was launched bringing third-party apps and the means of installing it to the users. And a serious collection it is: as of Summer 2016, it covers 155 countries and contains more than two million apps. It also has paid out around fifty billion US dollars in revenue to the developers since its launch in 2008. Huge growth is also noticed – it was only forty billion on the start of the year, so it is up for a quarter in half a year.
Each year Apple releases a major iOS version update, with its latest incarnation, the iOS 10, been released this September. Though not all the devices are to receive those updates, support for older ones is limited. For instance, the iOS 10 works on iPhones 5 and newer, abandoning all the previous models, same for the iPads – 4 and above, iPods – 6th gen only, iPad Mini 2 and iPad Pro.

"We create breathtaking designs of iOS applications thanks to significant number of useful features this mobile platform has. The iOS apps developed by MWDN always function well thanks to the implementation of the best user experience solutions."

Since iOS 4, multitasking, though limited, is accessible in all new iOS versions. Apps are quite strictly confined in their background activities, yet some tasks, like notifications, background audio and background location are available. There is also a “task completion” option available for apps with up to ten minutes of work allowed in background, still downloading is impossible in non-active apps.
As for now iOS is the second (after Android) most common operating system on this planet, and that is a pretty amazing result for a single software/hardware brand.