I'll probably avoid jumping to the very latest Inno Setup version for the release version of Sigil for a bit. When I jumped to 6.4 too early, one of the various Windows repository's tools could not extract the contents of Sigil's installer. I learned to stay a bit behind on this just in case. No problem at all updating to the very latest for personal builds, though!
Here was the issue with ScoopInstaller and Inno 6.4 for any interested:
https://github.com/ScoopInstaller/Extras/issues/14717