macOS X 10.10 Yosemite was released on October 16, 2014. It features a redesigned user interface similar to that of iOS 7, intended to feature a more minimal, text-based 'flat' design, with use of translucency effects and intensely saturated colours. Apple's showcase new feature in Yosemite is Handoff, which enables users with iPhones running iOS 8.1 or later to answer phone calls, receive and send SMS messages, and complete unfinished iPhone emails on their Mac. As of OS X 10.10.3, Photos replaced iPhoto and Aperture.
List of compatible machines:
• MacBook (late 2008 aluminium, or early 2009 or newer)
• MacBook Pro (mid/late 2007 or newer)
• MacBook Air (late 2008 or newer)
• Mac mini (early 2009 or newer)
• Mac Pro (early 2008 or newer)
• Xserve (early 2009)
• iMac (mid 2007 or newer)
You will need at least 2GB of RAM and 8GB of free storage to run it, while users already running Mavericks (Mac OS X 10.9) need not worry about compatibility issues.