The macOS Sierra 10.12.3 Update improves the stability and security of your Mac, and is recommended for all users.

This update:

• Improves automatic graphics switching on MacBook Pro (15-inch, October 2016).
• Resolves graphics issues while encoding Adobe Premiere Pro projects on MacBook Pro with Touch Bar (13- and 15-inch, October 2016).
• Fixes an issue that prevented the searching of scanned PDF documents in Preview.
• Resolves a compatibility issue with PDF documents that are exported with encryption enabled.
• Fixes an issue that prevented some third-party applications from correctly importing images from digital cameras.
• Enterprise content: Resolves an issue were network or cached user accounts (such as Active Directory accounts) using the maxFailedLoginAttempts password policy were becoming disabled.

See Apple Security Updates for detailed information about the security content of this update.

https://support.apple.com/de-de/HT207462
https://support.apple.com/de-de/HT201222