“Microsoft has taken another step on its gargantuan journey to fortifying more than a billion PCs worldwide against Meltdown and Spectre vulnerabilities. This week’s Patch Tuesday release updates PCs running x86 versions of Windows 7 and 8.1 against Meltdown, meaning that all currently supported Windows releases now include defense against this vulnerability.”
Source: Microsoft fixes more Meltdown and Spectre flaws in Windows