Customers who purchase Microsoft Office 2010 between 19 October and 30 April 2013 will later have the option to upgrade to Office 2013 for free.

The offer is open to customers of a multitude of separate packages, who can choose between upgrading for free when Office 2013 comes out and getting a subscription to the cloud-based Office 365 Home Premium for a year.

Those who buy a new PC with Office 2010 pre-installed (between the above dates) will also be entitled to access the offer. Unfortunately, those who bought the product before the opening of the window do not qualify.

In order to upgrade, customers must provide proof of purchase and a legitimate product key.

Subscribers to alternative versions of Office will be restricted to upgrading to variants of Office 365. For example, users of Office University 2010 will be subject to an upgrade to Office 365 University.

Customers planning to splash out on the imminent Surface RT might not need to worry about all of this, as it has recently been reported that the tablet will ship with the final version of Office 2013, rather than the preview edition that Microsoft previously reported.