Use --force with brew install?

[lmakarov]

Looks like brew/cask may not always detect updates.

Currently, Homebrew-Cask cannot always detect if an application has been updated. You can force an update via the command brew cask install --force. We are working on improving this.

We may have to force the install in order to get things updated for existing users:

brew install virtualbox --force
brew install vagrant --force

https://github.com/blinkreaction/boot2docker-vagrant/blob/develop/scripts/presetup-mac.sh#L31
https://github.com/blinkreaction/boot2docker-vagrant/blob/develop/scripts/presetup-mac.sh#L38

The downside of this is a full reinstall every time prerequisites are installed, which is far from being ideal.