Apple today seeded the second beta of OS X 10.10.4 to developers



From MacRumors:

Developers can download the new beta, build 14E11f, through the Software Update mechanism in the Mac App Store or through the Mac Developer Center. OS X 10.10.3 introduced several consumer-facing changes including the new Photos for OS X app, a redesigned emoji picker, new diversified emoji, and more, but OS X 10.10.4 appears to be an under-the-hood update that brings performance enhancements and bug fixes.

  Apple Seeds Second OS X 10.10.4 Yosemite Beta to Developers, First Public Beta Version