I’ll introduce how to update and upgrade Homebrew, the macOS package manager.
Updating Homebrew
Update when homebrew itself is updated or when Formulas are added/changed.
brew update
Upgrading Packages with Homebrew
“The difference between upgrade and update is that update ‘refers to small-scale software updates, providing bug fixes and slight feature improvements,’ while upgrade ‘refers to major software improvements being released as a new version.’” according to the Japanese explanation (「アップグレードとアップデートの違いは、アップデートが『ソフトの小規模な更新を指し、不具合の修正・わずかな機能向上などが提供される』のに対して、アップグレードは『ソフトに大幅な改良がされ、新バージョンとして公開されること』。」).
Also, before running this command, you need to complete the update with the brew update command.
brew upgrade
That’s all from the Gemba, where I regularly update and upgrade Homebrew.