Microsoft has released the Windows 10 KB4482887 cumulative update for build 1809. The update is available to all Windows 10 October 2018 Update (build 1809) users and can be installed through Windows Update. It includes a fix for an annoying Action Center bug, and numerous other bug fixes. The fixes will not be enabled immediately, but will be done so over the next few months in order to make sure new issues do not pop up when utilized publicly. In order to use these mitigiations users will need to be using an AMD processor or Intel Broadwell processors.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-update-kb4482887-released-with-performance-fix-for-spectre-bug/