The developer of this app needs to update it to work with this version of macOS. Contact the developer for more information.

The message is pretty clear...

Whatever it is you're trying to install, it is not compatible with macOS Catalina.

Catalina no longer supports 32 bit applications.

Contact the developer of the app you're trying to install and find out if there is a 64 bit version available.

sensori wrote:

I have this question too, and the program I am trying to install is a 64-bit program. So that's not necessarily the problem.

I can not see your system. Please provide the name and version of the app, the year/model of your computer, the operating system version you are running, and the exact error you are encountering.

BDAqua wrote:

But which program is it, or any other clues you can give us?

Download and use Go64, and—depending on your local expectations and app requirements—find and remove, or find and update, or find and replace, all 32-bit apps found.

I have this question too, and the program I am trying to install is a 64-bit program. So that's not necessarily the problem.

But which program is it, or any other clues you can give us?

Good advice, thanks ! :)