I'm getting this error:
due to my Java version. I would like to make a .jar file compatible with older versions of Java as well as newer versions. My PC isn't a problem but my audience uses older versions of Java. How could I make my program compatible with older versions as well as newer versions and how far should i go with it?
You could go back and compile your sources and generate a new jar file with an older javac thats compatible with the particular version of java.