If you’re anxious to try, Photos, the successor to both iPhoto and Aperture, is now available as a public beta for the first time ever.
Apple released a beta version of OS X Yosemite 10.10.3 that includes the first early access to the new Photos app on OS X. The public beta is available now to all registered public beta testers.
Other new additions included in OS X 10.10.3 include a new single-pane emoji scroller, racially diverse emoji, and two-factor authentication for Google. You can download it through the Mac App Store.