iPhone OS 4.0 is on its way. There have been hints that we’d see the next version of the software that powers the iPhone and iPod Touch soon, and Apple sent invitations to a media-only preview of the software on Thursday, inviting us to “get a sneak peek” at iPhone OS 4.0.

Apple isn’t going to let on what’s in the updated iPhone software until then, but there’s been some buzz recently about what Apple might have in the works.

When version 4.0 of the software will be available for download still isn’t clear. Thursday is likely just an overview of new features, though Apple might give at least a time frame for the software’s release. The best guess is that it will coincide with the release of new iPhone hardware, which has happened in late June or early July every year since 2007.

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