In the last few weeks, AppleInsider has seen more than 30 total visits from machines listed as running OS X 10.9. A handful of machines running Intel-based OS X 10.9 Macs have also been sighted elsewhere on the Web.
While such information can be faked, the growing number of appearances of systems claiming to run OS X 10.9 could indicate that Apple is already testing early betas of the next major update to its Mac operating system.
For the last couple of years, Apple has been upgrading OS X on an annual basis. The latest version, OS X 10.8 Mountain Lion, debuted on the Mac App Store in July, and OS X 10.7 Lion launched in July of 2011.
Prior to that, OS X 10.6 Snow Leopard launched in August of 2009, while OS X 10.5 Leopard saw its initial release in October of 2007.
It's currently unknown whether the next major version of OS X, which remains unofficial and unnamed, will debut in the summer of 2013, about a year after the launch of Mountain Lion. OS X 10.8 got off to a strong start this year for Apple, with 7 million upgrades sold in less than two months.