How to update formula

To update a formula, the following fields need to be upgraded:

All those fields are strings.

You can directly update from /usr/local/Library/Taps/skippbox/, this will help for debugging install, testing, and audit.

Test the formula installation with:

$ brew install --debug --verbose $FORMULA_NAME

If the installation goes well, you can test and audit the formula for styling (just to be sure):

$ brew test $FORMULA_NAME
$ brew audit --strict --online $FORMULA_NAME

And you are done :)

OS X application bundle (.app)

Those applications are rejected in Homebrew, a specific project exist for that: Homebrew Cask

The formulae are sensibly the same, but you need to put those in the Casks folder and use the brew cask command:

$ brew cask install skippbox

Nice to have resources on hombrew.