Download macOS Sierra 10.12.6 Update
The macOS Sierra 10.12.6 update improves the security, stability and compatibility of your Mac, and is recommended for all users.
For more detailed information about this update, please visit: https://support.apple.com/kb/HT207835
For detailed information about the security content of this update, please visit: https://support.apple.com/kb/HT201222