WSJT-X 2.7.0 rc3 (modified for use with "Otto"), download the installer from the release page:
https://github.com/avantol/WSJT-X_2.7.0/releases/tag/v2.7.0-185
Download Otto.msi at https://github.com/avantol/WSJTX-Controller-v2
When running the installers, at the Windows warning message, click "More info" then "Run anyway".