One month after Apple released OS X 10.9.4 to the public, the company has seeded the first beta of OS X 10.9.5 to developers. The update is available through the Software Update feature in the Mac App Store and in the Mac Dev Center. It has a build number of 13F7.
This is likely to be a small update, with bug fixes and stability enhancements making up the majority of the changes. Apple has asked developers to focus on Graphics, Safari, USB, and USB Smart Cards with this release.
Apple is now running two OS X Betas simultaneously: Yosemite and Mavericks 10.9.5. It’s likely that this will be the last proper update to Mavericks, since Yosemite is scheduled to launch in the fall. After that Apple will probably just release occasional security patches for Mavericks, as it has done with older versions of OS X.