The tool should be good for 12.1 as well - have tested it myself and worked fine. Just make sure you are using the right version for 12.1 - can be downloaded from here:
https://www-secure.symantec.com/connect/downloads/new-sep-content-distribution-monitor-gup-health-checking
Remeber as well you need to copy all the tool files into the SEPM folder location - "Symantec Endpoint Protection Manager\Tools"
VIDEO about the tool:
https://www-secure.symantec.com/connect/videos/sep-content-distribution-monitor-introduction