Everyone was expecting Microsoft to unveil Office 15 this week, but it turns out that they were off by about 350.

The new Office 365 is major shift in both features and function for this 13 year old office suite,and it is set to be released in four editions (Home Premium, Small Business Premium, ProPlus, and Enterprise).

The base version of the app suite is Home Premium, and it’s going to allow for installation on up to 5 computers per license and it comes with 20GB of SkyDrive storage as well as 60 minutes of Skype credit per month. This version includes Outlook, OneNote, Access, Word, PowerPoint, Excel, and Publisher for apps.

Next up is Small Business Premium. Like the name says, it’s intended for a business with up to 10 employees, and those 10 employees can each install Office 365 on up to 5 computers. This version includes Word, PowerPoint, Excel, Access, Publisher, InfoPath, Outlook, OneNote, and Lync.

ProPlus includes 25 user accounts, again with the ability to install on 5 computers. ProPlus has the same apps as the Small Business Premium, so it’s really more of a bulk license deal than a new version of Office 365. And Office 365 Enterprise has the same apps and userbase as Proplus, but it also adds the ability to archive and hold a company’s email in Exchange Online.

Microsoft hasn’t released any pricing details, and the final release dates have not been set just yet, but you can download a preview today.