Microsoft isn't calling it a "tech guarantee", but they have announced that Office 2010 purchases made after Oct 19 2012 qualify for 1 year subscription to Office 2013, free of charge.
The subscription includes the rights to use Office 2013 or Mac Office on up to 5 computers. It also includes more Skydrive storage space, Skype minutes and a few other things but does not include an Online Exchange online mailbox. Exchange accounts are available in the more expensive small business subscriptions (or available separately).
My recommendation: if you are thinking about buying Office 2010, it's well worth it to wait a little longer and take advantage of the free offer.
Buy Office 2010 and get one year free of Office 365 Home Premium
Starting October 19, people who purchase Office 2010 or Office for Mac 2011 will qualify to download, for free, one year of Office 365 Home Premium or the equivalent Office 2013 offering, when available. Small business customers in applicable markets will also be eligible for a three-month trial of Office 365 Small Business Premium.
Get more information on pricing for the Office 2013 and the offer at the Office blog at The new Office 365 subscriptions for consumers and small businesses
Published on September 21, 2012