Are there plans to upgrade KmyMoney for Windows 10 to version 5.0 ?

Your question is vague. Do you mean 1) Is there a version 5.0.x specifically for Windows 10 or 2) Is Version 5.0.x available for the Windows platform. If the latter, then yes. Visit https://kmymoney.org/build.php to see a list of stable and nightly builds.

It looks like there's an issue with the stable build at the moment as there's an error and the D/L link isn't present. I'm using the latest available version of the stable release.

Robert