Name Mangler 2.5.1 is out, available for direct customers via in-app updating (or by downloading the full version from our site), and for App Store customers via the Updates tab in the App Store application.
There’s only one change in this version, but it’s an important one. If a rename operation will remove the extension from one (or more) filenames, then Name Mangler will ask you to confirm that this is what you really want to do.
In older versions of Mac OS X (and the Mac OS in general), the loss of an extension wasn’t a big deal—the system didn’t rely on extensions to determine which program should open a given file. Now, however, extensions are quite important; remove the extension from a PNG file, for instance, and OS X will probably think that file is now a Unix Executable file. It’s important to note that the file itself hasn’t been damaged; if you put the extension back, it will work as it did before.
Given OS X’s relatively new reliance on extensions, we felt it important that Name Mangler ask you to reconfirm your intent to remove filename extensions before doing so.