Keep Homebrew up to date with 'brew update'. Homebrew core packages are updated as often as every day, so it is likely you will see updates. The commands 'brew update' and 'brew upgrade' are different. Update is for Homebrew itself. Upgrade is for individual software packages. As you use Homebrew, it is helpful to see a list of all the packages you've installed with the command 'brew list'. Then use 'brew update' to freshen Homebrew and 'brew upgrade' to install newer packages.