This update (choose Window->Updates from within Photoshop) enables remote connections between Photoshop CS5 and other apps, including the new Adobe Nav, Eazel, and Color Lava for iPad. According to the release notes,
The 12.0.4 update also fixes Liquify performance, type-related crashes, and other top customer issues. The most significant fixes include the following:
- A number of potential security vulnerabilities have been addressed.
- Liquify save mesh now works as expected.
- An issue with Sharpen crashing has been fixed.
- An issue with Quick Selection crashing has been fixed.
- The Orphea Studio File Info issue has been resolved.