TeXShop is automatically installed by the MacTeX packages described in the previous section. It is also possible to obtain it from the TeXShop web site:
pages.uoregon.edu/koch/texshop/
New versions of TeXShop sometimes have revised Macros, Engines, and Templates. These new versions do not automatically appear when updating from an older version of TeXShop. To get them, read "About This Release" under the Help menu.
A brute force way to get new defaults is to go to ~/Library/TeXShop; here ~/Library is the Library folder in your home directory. Move the entire Macros (or Engines or Templates) folder to the desktop. The next time TeXShop runs, it will recreate the missing folder. Then merge in any personal changes you may have made from the old folder on the desktop.
Much easier ways to update are described in Help's "How do I configure TeXShop?" section.