I've tried it on Windows 11. With your information I've searched again and found (my) problem now! First: Thanks for that! 

What was the problem?  
I've installed IRIS using the custom option and selected to install ALL items on the hard disk. Then I cannot find the odbc driver dll in the following folder:

All the other drivers are there: dotnet, java and so on.

Now I've tried a client installation on a fresh Windows... the folders are still empty. BUT the ODBC Data Source Administrator shows the 2024.1 IRIS ODBC driver! 
Again: The CLIENT install works!

The files are located here:


The puzzle is solved. Thanks to all of you!

Andreas
 

Thanks for the link! 
I know this link, but unfortunately it seems that only real?! customers can access it! I've got this message: 
Personally, I have never bought a Caché\IRIS licence, but have worked for companies that have such access. At home ;-) I only use the Community Edition. So the message could be plausible.
Andreas

The last element is the namespace not the schema, please see here: Using the JDBC Driver | Using Java with InterSystems Software | InterSystems IRIS Data Platform 2024.1

jdbc:Cache://<host>:<port>/<namespace>

Andreas