Legacy Cumulus 1 release 1.9.4 (build 1099) - 28 November 2014
(a patch is available for 1.9.4 build 1099 that extends the date range of drop-down menus to 2030)
Download the Software (Cumulus MX / Cumulus 1 and other related items) from the Wiki
From Cumulus MX version 3 build 3044 the development baton passed to Mark Crossley. Mark has been responsible for all the Builds since, and has recently released Cumulus MX version 4. He has made the code available on GitHub. It is Mark's hope that others will join in this development, but at the very least he welcomes your ideas for future developments (see Cumulus MX Development suggestions).
Just create a shortcut like you did before, but instead of setting the Target to "<path>Cumulus MX.exe", make it "dotnet <path>Cumulus MX.dll", and set the Start in option to <path>.