if you're still running 11.x then yes you need to upgrade your SEPM to the latest version, 12.1.5
If you're running 12.1 then no, you technically don't need to upgrade the SEPM as the 12.1 SEPM can manage all versions of 12.1. You would just need to import the client package.
However, it is best practice and recommended to be at the same version for both client and manager.
Follow this for all guidance:
Upgrading or migrating to Symantec Endpoint Protection 12.1.5