My test version of Sigil (built entirely with versions of Visual Studio earlier than 17.10), works fine with the 8.11 Calibre Open With (and its msvcp140.dll v14.36) and works fine with any of the pre 14.40 runtimes I've tested it with.
There may come a time when an official release of Sigil will need to break binary compatibility with older Visual Studio 2015-2022 VC++ runtimes, but it is not THIS day.
This means that GitHub CI builds of Sigil might (or might not; we'll see) need Post-14.40 Visual Studio 2015-2022 VC++ runtimes to work (and might not work with Calibre's Open With), but there's little to do about that.