Two different locations for Homebrew I had a 3-year old installation of Homebrew in /usr/local/Library/Homebrew. It didn't update properly, so I reinstalled it (without, unfortunately, uninstalling first). This time, Homebrew installed in /usr/local/Homebrew. 

Not only are the folder locations different, but the subfolders also are different. Is the old installation deprecated and can I delete it? Or does the new installation depend on the old installation? This is under Mac OS Sierra.
I'm sure new installations of Homebrew are installed under /usr/local/Homebrew/, so I see no harm in deleting the old installation. I also noticed I have no /usr/local/Library/ in my Sierra file structure.

To keep things tidy you might still be able to delete the old installation using the script which has more uninstall options.