ITunes

iTunes is Apple's music and video management software. It also serves as a desktop client for the iTunes Store and handles iOS device synchronization.

It consists of two major components: iTunes itself, and Apple Mobile Device Support (AMDS). Apple Mobile Device Support is the component responsible for synchronizing with iOS devices. Previous versions included QuickTime, which was used for media playback.

From version 9 to 12.10.8.5, iTunes on Windows includes a component called Apple Application Support, which includes WebKit and some other Apple libraries and tools. It is used to display the iTunes Store, as well as iTunes LPs and iTunes Extras.

Version History
Only versions 7.3.0 and newer are included; anything before did not contain support for the (then non-existent) iPhone.

As of macOS Catalina, iTunes has been replaced by separate Music, Podcasts, TV, and Books apps, with iOS device functionality merged into Finder. iTunes 12.9.5.5 is the final release on macOS, bundled with macOS Mojave 10.14.6 Supplemental Update (Build 18G95).

Additionally, since at least macOS High Sierra (possibly as early as the introduction of System Integrity Protection in OS X El Capitan), Apple Mobile Device Support handles its own updates. When a device unknown to the currently installed build of AMDS is connected, MobileDeviceUpdater.app prompts the user to install a software update. Previously, AMDS would only be updated by installing a full iTunes or Xcode update.

iTunes is still in use on Windows, however it is soon to be replaced by the Apple Music, Apple TV, and Apple Devices apps, currently in preview.

Older video cards
For with iTunes 12.1, Apple bundled 64-bit versions of Apple Mobile Device Support and Apple Application Support with iTunes. For iTunes 12.1 through 12.4.3.1, Apple also offered a version for 64-bit Windows computers with older video cards, which keep the 32-bit versions of said libraries. Installing this version is necessary when using a 32-bit program expecting 32-bit libraries, such as many older jailbreak/jailbreak-related tools.