Under the Microsoft Office 2010 Technology Guarantee (also known as the Tech Guarantee) scheme, consumers that purchase and activate a copy of Office 2007 between March 5 and September 30, will be able to download the equivalent version of Office 2010 for no extra cost.
The scheme applies to PC owners that purchase the software on its own, or pre-installed on a new PC. Alternatively, the upgrade is available on disc, although a charge applies for this. Microsoft has not yet released details of the disc fee.
However, Microsoft said students and teachers that purchase discounted versions of Office through its education scheme, and consumers who buy second-hand licences for the software using auction sites such as eBay will be excluded from the scheme.
The move comes a month after Charles Van Heusen, a Texas-based Microsoft technology specialist, posted information about the upgrade scheme on the web.
Microsoft Office 2010 is expected to be released in June and will feature Web Apps - a web-based version of the productivity suite that will allow web users to open, view and make 'lightweight' edits to Office documents on any PC via a web browser, even if it doesn't have the software installed.
Last month, Microsoft revealed Office 2010 will be priced from £109.99 in the UK for a boxed copy of Office 2010 Home and Student, which includes Word, Excel, PowerPoint and OneNote and can be installed on up to three computers.
A copy of Office 2010 Home and Business that also includes Outlook and can be used on two PCs costs £239.99, while Office 2010 Professional offers all of these programs along with Publisher and Microsoft's desktop database software, Access, for £429.99 for a two-PC licence.
See also: Microsoft reveals Office 2010 UK pricing