Eric Schlegel, one of Apple’s Carbon engineers, posted this today on the carbon-dev list: "Hi everyone, As you’ve heard, there are enhancements to fullscreen support in OS X Mavericks, and Carbon apps are included. If you’re at the conference and you have any questions about Carbon fullscreen support in Mavericks (or Lion/Mountain Lion), look for me at the Cocoa Fullscreen lab on Thursday morning, 9-10am, Frameworks Lab A. -eric" Besides the report from Steve C confirming FB-created apps run in Mavericks, this additional feedback provides some assurance of Mavericks shipping with Carbon. BTW/FWIW: Apple’s continued use of Carbon in some of its own apps ( iTunes 11 is a notable example ) is, IMO, a major reason Carbon still exists in Mavericks. Hopefully, FBers with apps that must run post Carbon are busy making appropriate changes/plans. Brian S.