Microsoft is rewarding its "best customers" who have not yet upgraded from the Xbox 360 to the Xbox One with a $75 credit to do so, according to a poster on the video game forum NeoGAF.

Microsoft confirmed Tuesday that select Xbox 360 owners in the United States would receive an upgrade offer when they signed in to Xbox Live. The screen thanks the user for "being an Xbox fan" and says he will receive the credit after registering the Xbox One with an Xbox Live username.

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The offer, according to the terms and conditions screen that was presented by NeoGAF user BeforeU, lasts until the end of July. After a user registers his new Xbox One, the $75 credit will be attached to his Xbox Live account, which can be used to purchase games and other content digitally.

The offer says the $75 must be redeemed by Oct. 14 and spent within the following year.

The Xbox One has sold 5 million consoles worldwide since launch, according the last numbers released by Microsoft in April. Despite not updating those numbers in nearly three months, we know from NPD numbers that Sony's PlayStation 4 has beaten the Xbox One in sales every month since release.

Microsoft slashed the Xbox One price starting last month to $399 to match the PlayStation 4, which it did by unbundling the Kinect motion controller from the console.