OS X 10.10.4 BETA 6 build 14E36b has been released to all those who are currently registered on the public BETA test program (or who have a Apple Developer account) 10.10.4 focusing on fixing some of the bugs reported in 10.10.3. Most importantly replacing discoveryd networking daemon with the mDNSResponder as seen in Snow Leopard. Discoveryd has been at the forefront of many a complaint of Yosemite users due to its instability.
There’s currently no news on when 10.10.4 will be released as an update to the general public. However, this isn’t unusual for incremental OS X updates. Normally the BETA’s spend a couple of weeks in ‘testing’ before being released.
OS X 10.10.4 BETA 6 is available to download using the normal App Store route, or by logging into the Apple Developer Portal.