For people on Version 1903: KB4497936 is here:
Changelog (build 18362.113):
• Provides protections against a new subclass of speculative execution side-channel vulnerabilities, known as Microarchitectural Data Sampling, for 64-Bit (x64) versions of Windows (CVE-2018-11091, CVE-2018-12126, CVE-2018-12127, CVE-2018-12130). Use the registry settings as described in the Windows Client and Windows Server articles. (These registry settings are enabled by default for Windows Client OS editions and Windows Server OS editions).
• Addresses an issue that decreases Internet Explorer’s performance when you use roaming profiles or you don't use the Microsoft Compatibility List.
• Addresses an issue that may cause the text, layout, or cell size to become narrower or wider than expected in Microsoft Excel when using the MS UI Gothic or MS PGothic fonts.