No, it is not a hoax. Yes, we know that iPhone OS 4 exists, because Apple has actually released a beta version of the software to iPhone OS 4 to developer programme members.
The iPhone OS 4 beta release includes an updated software development kit (SDK) with more than 1,500 new application programming interfaces and 100 new features that will be available to iPhone and iPod touch users this summer.
The new features include multitasking for third party applications; folders to better organise and access applications; improved mail with a unified inbox, fast inbox switching and threaded messages; enhanced enterprise support with even better data protection, mobile device management, wireless application distribution; Apple's new iAd mobile advertising platform; and iBooks.
iPhone OS 4s new multitasking offers users a new way to quickly move between applications and provides developers seven new multitasking services; it has a unified inbox, allowing users to see messages from all their email accounts displayed together in a single inbox.
iAd, Apple's new mobile advertising platform, displays full-screen video and interactive ad content. iPhone OS 4 lets developers easily embed iAd opportunities within their applications. Apple will sell and serve the ads, and developers will receive an industry-standard 60 per cent of iAd revenue.
The iPhone OS 4 beta release includes a developer preview of game centre, which contains a set of APIs that allows developers to create applications that will allow multiplayer games.
New enterprise features in iPhone OS 4 include improvements in security, scalability and compatibility. The new mobile device management service can be integrated with third party servers to wirelessly configure, query and even wipe or lock managed iPhones. It enables enterprises to securely host and wirelessly distribute their own in-house developed apps to employees.
The new data protection feature provides a longer, more complex passcode than before, serving as an encryption key to protect data on the phone. The iPhone OS 4 beta software and SDK are available at developer.apple.com.