People familiar with the matter said build 10F50 of Mac OS X 10.6.4, seeded to Apple's developer community, is a 581.3MB file. The delta build has many of the same fixes found in the previous build issued to developers last week.
The only change specifically cited by Apple is an improvement in VoiceOver compatibility with the iMovie and GarageBand applications. The previous build had focused generally on VoiceOver, but did not specifically mention the iLife software.
The latest build also reportedly has just one known issue related to incorrectly formatted marketing text.
Focus areas for the latest build include Graphics Drivers, SMB, USB, Voice Over and VPN, according to developers testing Mac OS X 10.6.4. The build, like the last one, resolves an issue that could cause inputs such as the keyboard or trackpad to become responsive, and also addresses a problem that prevented some Adobe Creative Suite 3 applications from loading.
The latest build also reportedly improves the reliability of VPN connections, addresses a problem that arose while editing photos in a full-screen view with iPhoto or Aperture, and fixes a playback problem that arose when using "Good Quality" deinterlacing while watching a DVD.
The first beta of Mac OS X 10.6.4 arrived in late April, with which Apple asked developers to test four key areas of the system: graphics drivers, Windows file sharing, USB devices and Voice Over.