Microsoft's Windows 8 Pro upgrade discount will expire in about three weeks, at which point the company will triple or even quintuple the current price of the new operating system, according to several online retailers.

On Friday, Microsoft reminded customers that a different upgrade deal will expire Jan. 31 -- one that lets purchasers of new Windows 7 PCs acquire Windows 8 Pro for $14.99 -- but made no mention of the same deadline for an upgrade from Windows XP, Vista and Windows 7 on older PCs.

That discount, also set to end Jan. 31, prices a download upgrade to Windows 8 Pro at $39.99, or $69.99 for a DVD.

Microsoft announced both deals in mid-2012, and began selling the upgrades in October when Windows 8 debuted in retail.

According to online retailers, including Amazon, Newegg and TigerDirect, the DVD-based Windows 8 Pro upgrade carries a suggested list price of $199.99, or nearly triple the now-discounted price of $69.99.

Although Microsoft has repeatedly declined to comment on post-January pricing plans for Windows 8 Pro, its past pricing practices sync with the $199.99 list price: An upgrade to Windows 7 Professional, analogous to Windows 8 Pro, has always been priced at $199.99. Microsoft's e-store currently lists it at that price.

It's unknown whether Microsoft will continue to sell Windows 8 Pro as a download after the discount expires, and if it does, at what cost. If the price of a download is identical to the boxed copy -- Microsoft has priced downloads and DVDs identically in the past -- then the OS price will jump five-fold on Feb. 1.

Computerworld