What is the earliest version / what versions of Java are required for Java Rules Manager to work with?

Netwrix Endpoint Policy Manager (formerly PolicyPak) Java Rules Manager will work when Java 7 U 40 or later is on the machine. Then you can make maps to any version of Java higher or lower.

Keep in mind that PPJRM will not work without at LEAST Java 7 U 40 installed on the machine.