Click Update Now or Upgrade Now: Update Now installs the latest updates for the currently installed version, such as an update from macOS Big SurmacOS Big SurmacOS Big Sur 11.4 adds Apple Podcasts subscriptions and channels and includes important bug fixes. This release also fixes the following issues: Bookmarks in Safari may get reordered or moved into a folder that can appear hidden. Certain websites may not display correctly after your Mac wakes from sleep. 11.5 to macOS Big Sur 11.6. Upgrade Now installs a major new version with a new name, such as macOS MontereymacOS MontereymacOS Monterey (version 12) is the eighteenth and current major release of macOS, Apple's desktop operating system for Macintosh computers. The successor to macOS Big Sur, it was announced at WWDC 2021 on June 7, 2021, and released on October 25, 2021..