This security update includes improvements and fixes that were a part of update KB4103719 (released May 17, 2018) and addresses the following issues:

Addresses an issue where firmware updates cause devices to go into BitLocker recovery mode when BitLocker is enabled, but Secure Boot is disabled not present. This update prevents firmware installation on devices in this state. Administrators can install firmware updates by:
1. Temporarily suspending BitLocker.
2. Immediately installing firmware updates before the next OS startup.
3. Immediately restarting the device so that BitLocker doesn’t remain in the suspended state.
Security updates to Internet Explorer, Windows apps, Windows storage and filesystems, Windows Server, and Windows wireless networking.

For more information about the resolved security vulnerabilities, see the Security Update Guide.