In addition to the current beta testing of iOS 9 and OS X 10.11 El Capitan, Apple continues to work on updates for the latest operating systems iOS 8 and OS X 10.10 Yosemite. These are now available also in the form of new beta version.
With iOS 8.4.1 (build 12H304) and OS X 10.10.5 (Build 14F6a) Apple has just released the first beta version of the currently available operating systems.
The test versions has provided in the Developer Portal for its registered developers to download Apple. What specific innovations bring the two updates is not yet known.
In the Release Notes for the beta of OS X 10.10.5 (via 9to5Mac) is only talk of improvements in the stability, compatibility and security.
Apple had published in the past week both the third developer beta of iOS 9 and OS X 10.11 El Capitan, and the first public beta of the upcoming operating systems.