The download for the release candidate for 6.5 is here:
https://ascom-standards.org/Downloads/Index.htm
Wins 10 won't let you install it and you'll get a message saying its been blocked and either keep or delete it. You have to click keep and then 2 2nd menu item comes up about keeping it. Once clicked you'll then have the standard Windows blocking message where you click run anyway.
A bit of a chore to find all this out and not very straight forward. The files are not labelled in an easy to understand way so use the above link the clearly marked download here for this file is top right of the page!
The Github site is a mess. I bet the programmer has a very messy bedroom!
Greg.