The number of apps peaked at around 2.2 million in 2017, but declined slightly over the next few years as Apple began a process to remove old or 32-bit apps that do not function as intended or that do not follow current app guidelines. The App Store was opened on July 10, 2008, with an initial 500 applications available. Apps can be downloaded on the iPhone, iPod Touch, or the iPad, and some can be transferred to the Apple Watch smartwatch or 4th-generation or newer Apple TVs as extensions of iPhone apps. The store allows users to browse and download approved apps developed within Apple's iOS Software Development Kit. The App Store is an app store platform, developed and maintained by Apple Inc., for mobile apps on its iOS and iPadOS operating systems. For the tvOS version of the app store, see Apple TV App Store. For the macOS version of the app store, see Mac App Store.
