Apple has changed the naming of their software products some time ago. Therefore, you will not get any new version of OS X. Apple’s operating systems for desktops and laptops are called macOS.
Now you can try new version of macOS by yourself by downloading the open beta version. This new Apple’s operating system is called macOS Sierra. It was presented first time during the Apple’s conference, i.e. WWDC (Worldwide Developers Conference) 2016. The final version of the newest macOS will be available in September this year.
I bet that you are interested in new features from Apple.
In macOS Sierra you will find redesigned iTunes application and new file system APFS which is optimized for SSD hard drives and strong encryption features. Apple has prepared also new photo view application which is able to recognize places, faces and situations (e.g. a party). It also creates new photo albums automatically. The next interesting new feature is called Continuity. The integration of Apple devices is great and well designed, but now you will able to use your iPhone and macOS desktop/laptop in the same way. Apple has also implemented Auto Lock feature, it means that your computer will be locked automatically when you will be away and it will unlock when you come back. You will be authenticated basing on your iPhone or Apple Watch device.
Of course, you have to remember that this is still a beta version.
If you want to test new operating system from Apple, you have to sign in to Apple Beta program. However, the final version will be available in autumn, so you can also wait about 3 months on the stable version of macOS Sierra.