In the past, Apple has typically charged for major software updates, particularly for its OS X operating system. 过去,苹果通常会对重大升级收费,特别是OSX操作系统。
In response, Apple in 2004 issued an incensed statement, accusing RealNetworks of hacking the iPod and warning that future software updates might prevent songs sold by RealNetworks from playing on iPods. 作为回应,苹果2004年发表了一份愤怒的声明,指责RealNetworks对iPod实施了黑客攻击,并警告说,未来的软件更新版本将阻止RealNetworks的歌曲在iPod上播放。