THREAD before 3.1.4?

[Mark Felder]

Will THREAD be enabled before 3.1.4, or is it still considered too
experimental?

        // enable these when the tb problem is resolved
        //c.append( "THREAD=ORDEREDSUBJECT" );
        //c.append( "THREAD=REFS" );
        //c.append( "THREAD=REFERENCES" );