https://wccftech.com/april-patch-tuesday-windows-10-1803-1709/

Microsoft has started releasing the scheduled Patch Tuesday security updates for several versions of the operating system, including the April 2018 Update and the Fall Creators Update. The latter hits its end of service deadline today as version 1703 will no longer receive updates for Home and Pro users. As reported earlier, the May 2019 Update (currently in the Release Preview ring) is also receiving Patch Tuesday security updates.

Provides protections against Spectre Variant 2 (CVE-2017-5715) and Meltdown (CVE-2017-5754) for VIA-based computers. These protections are enabled by default for the Windows Client, but disabled by default for Windows Server. For Windows Client (IT Pro) guidance, follow the instructions in KB4073119. For Windows Server guidance, follow the instructions in KB4072698. Use these guidance documents to enable or disable these mitigations for VIA-based computers.