With Snow Leopard happily padding around hundreds of thousands of Macs around the world, it comes as little surprise to hear that Apple are already a few weeks into development of OS X 10.7. Sign of the upcoming OS refresh has been spotted in the change log of the open source "launchd" framework: a new entry for Mac OS build number "11A47" has turned up, and going by Apple's general nomenclature for build codes, that points squarely at OS X 10.7.
As MacRumors explains, "Apple's build numbering scheme utilizes a numerical prefix indicating the major release version, followed by a letter code indicating the minor release version and a numerical suffix indicating iterations of that version throughout its development." Therefore the 11A47 code suggests - with the 11 prefix - that this is a significant new version, since OS X 10.6.2, the most recent public update, was coded 10C540. Meanwhile the 47 suffix suggests there have been several iterations of the code before this version was spotted. Of course, there's no telling when we might see OS X 10.7 go live, especially given the time it took Apple to polish OS X 10.6.