Geert, thanks for the quick response. This article implies that the warning is a result of the CA not being trusted by Microsoft. Maybe your CA "Certum Trusted Network CA" is not trusted by Microsoft any more?

Hi,
I just learned about ShowMIDI from the 2024 MIDI Innovation Awards, and wanted to give it a try.
I downloaded ShowMIDI-Windows-0.9.0.exe and tried to install it.
I got this message:

On the right, the valid signature is verified. Does anyone know why this warning is given?