Apple today announced that OS X 10.9 Mavericks will be available as a free update today. Macs going all the way back to 2007 are eligible to install the new OS. You can download it from Apple here.

By comparison, Mountain Lion, the previous version of OS X, cost $20.

Mavericks, the tenth release of OS X, brings iBooks and Maps apps to OS X. It also includes a number of performance enhancements for extending battery life and reducing loading times. Apple SVP Craig Federighi claims that installing Mavericks on the latest MacBook Airs will give owners one extra hour of longer web browsing and 1.5 hours of iTunes video playback on a single charge.

Apple first unveiled OS X Mavericks at WWDC in June. The Golden Master version of the software was released to developers in early October.

You can head here for all our coverage of today’s event, or read a summary of all of today’s announcements in one handy list.

Image credit: Ezra Shaw / Getty Images

Related: With OS X Mavericks around the corner, here are 10 awesome OS X design concepts you have to see