Apple is pushing forward its development of iOS 8 and OS X 10.10, and each platform has received a new beta release today. This is the fourth release for both platforms and each has received stability enhancements.
OS X 10.10 has a few other updates that include a new UI for the calculator app, while dark mode has been tweaked to be more consistent across the UI. iOS 8 has a new Tips app that has tutorials to help you uncover new features in the update and orient new users to iOS. Both updates are supposed to fix various bugs and stabilize the platform too.
In addition to iOS and OS X 10.10, there is an update to iTunes 12 that has a flatter UI that matches that of OS X 10.10.
Apple will be launching both platforms later this year and both bring many new features to the mobile and desktop operating systems. You can take a look at OS X Yosemite here and iOS 8, here, to gain a better understanding of each operating system and what's on offer.
As always, pre-release software from Apple (or any other vendor) is intended for testing purposes only and should not be installed on production machines. If you do decided to test out the new builds, let us know if you find anything new in the comments below.