There's a new build of my client available at Release letsencrypt-win-simple v1.6 · win-acme/win-acme · GitHub
Here's the change log:
Check for IIS installed. Shouldn't crash if IIS not installed now.
Enable SNI for IIS 8. This will cause problems with IE on XP, but can be turned off and won't be set if there's an existing https binding.
Always prompt at end of program unless renew. No more disappearing errors when not running from console.
Store certs in "WebHosting" instead of personal.
Switch from letsencrypt-win lib submodule to ACMESharp nuget and latest API.
Removed the letsencrypt-win git submodule
Added references to latest ACMESharp (and related) nuget packages
Updated code to use latest ACMESharp namespaces and new CertProvider interface instead of deprecated CsrHelper
Includes support for auto-swiitching between 32/64-bit cert provider