On Tuesday, Apple released the seventh Developer Preview beta of its forthcoming OS X Mavericks (10.9) update. Registered developers can obtain the new version by signing into the Mac App Store with their developer account Apple IDs. The update has a number of changes contained in it, including new wallpapers, a new format for screen recordings, and the optional ability of users with non-Admin accounts to install software from (only) the Mac App Store. In addition, Apple released new Remote Desktop 3.7, Xcode 5 and Safari 6.1 betas….