An update for xScope is now available in the Mac App Store and through the in-app update. xScope 3.6.1 features more efficient processor usage which translates into less drain on your MacBook battery.
This update also includes more responsive tools, enhancements to Spaces and Retina Display support and various other improvements and bug fixes. Check out the complete list at the xScope version history page. If you are a developer and are using the current beta of OS X Mavericks you will definitely want to take a look at this latest version.
This is a free update for current users and is available now. Check your updates at the Mac App Store or, if you purchased from the website, check for updates under the xScope menu item.