Apple today seeded the second beta of OS X 10.10.5 to developers, two weeks after seeding the first 10.10.5 beta and one month after releasing OS X 10.10.4 to the public. Because we're just a couple of months away from the public release of OS X 10.11 El Capitan, it's possible that OS X 10.10.5 may be one of the last updates to Yosemite.
Today's beta, build number 14F19a, can be downloaded through the Software Update mechanism in the Mac App Store or through the Apple Developer Center.
The first OS X 10.10.5 beta did not appear to include any consumer-facing changes, so it's likely that this update focuses on behind-the-scenes bug fixes and performance enhancements.
Over the course of its lifespan, OS X Yosemite has received four updates. The first two brought bug fixes and security improvements, while OS X 10.10.3, the most significant update to Yosemite, introduced the new Photos app, Force Touch APIs, new emoji features, and more.
OS X 10.10.4, the current version of Yosemite, also focused on bug fixes and stability improvements, most notably introducing TRIM support for third-party SSDs and eliminating the Discoveryd process that caused ongoing connectivity issues in the OS.

















Top Rated Comments
Now...another....OS X El Capitan comes out and so far riddled with bugs to be worked out in the beta. OS X El Capitan is suppose to be the improvement over OS X Yosemite, but so far in the beta version has a long way to go.
This has happen every year since I can remember. We have to wait a year until the "New" OS X is stable and working properly and then considered "old" and outdated once it finally works...then another...
Humm....maybe in my mind I should think when a new OS X comes out officially, it is a beta for a year until it is finally stable. Just think that when the fall season occurs, the release of a new OS X is a preview edition until a year later...
I cannot believe what I am going to say: After twenty years of Microsoft's attempts at putting an OS out the first time that works out of the box....I think that finally hit it with Windows 10.....
Might have to stick with OS X Yosemite for awhile....
Snow Leopard...I am dreaming...
Thanks Apple, that was quick. Truly leading the pack with innovation right there.