Amazon is in the business of selling things, and it can’t sell things it doesn’t have. Certainly one thing Amazon wants to sell as many of as possible is the Kindle, but it’s completely sold out of the WiFi-only Kindle Paperwhite. You know what that means — new Kindles are probably incoming.The Paperwhite was the first Kindle with any kind of lighted display. It’s not backlit, though. The screen is reflective, so Amazon used a front-lit system with an LED at the edge, which illuminates a light guide layer on top of the touch panel. Before it went out of stock, the WiFi Paperwhite was going for $119 with special offers (ads). The ad-free version was $139. The $179 3G Paperwhite is still in stock.The Kindle Paperwhite came out almost a year ago, so it’s probably eligible for a refresh. Like all past Kindle’s the device has done well and gotten positive reviews — it’s currently sitting at 4.3 stars on Amazon. It could always be improved, though. If an update is in the works, Amazon could make the panel’s lighting a little more even. There are also no speakers on the current Paperwhite, which means no audio books or text to speech. That would be an easy fix.Amazon doesn’t usually make a big deal about iterative refreshes of the Kindle line anymore. The old version just vanishes or gets a price drop, and a new one starts shipping. That might be what we’re seeing here. The E Ink Kindles are cheap enough that a substantial number of users upgrade with the new version comes out — it’s in impulse-buy territory for a lot of people. So get your wallets ready.