Since Apple no longer lists Mavericks on the primary Mac App Store search, you may need to use these verified external repositories:
Hosted as a 5.7 GB optical disc image, available at the Internet Archive (10.9.5) .
Mac OS X Mavericks 10.9 ISO and DMG Image Download , released on October 22, 2013, was a landmark update for Apple as the first version of macOS offered as a free upgrade to users. It introduced over 200 new features, including the addition of iBooks and Maps to the Mac, enhanced multi-display support, and power-saving technologies like Timer Coalescing and App Nap.