Software

Like the iPhone, with which it shares a development environment^[86] the iPad only runs its own software, software downloaded from Apple's App Store, and software written by developers who have paid for a developer's license on registered devices.^[87] The iPad runs almost all third-party iPhone applications, displaying them at iPhone size or enlarging them to fill the iPad's screen.^[88] Developers may also create or modify apps to take advantage of the iPad's features.^[89] Application developers use iOS SDK for developing applications for iPad.^[90] The iPad originally shipped with a customized iPad-only version of iPhone OS, dubbed v3.2. On September 1, it was announced the iPad would get iOS 4.2 by November 2010;^[91] to fulfill this Apple released iOS 4.2.1 to the public on November 22.