Does 0, 6 do what you want? Or SAT, SUN? Or are they all broken at the moment?

Yes, everything works, no problem. It just caused me a lot of frustration as, according to Wikipedia, 7 should also work.

Yea, this is broken. Weekdays in Cron are

0 SUN
1 MON
2 TUE
3 WED
4 THU
5 FRI
6 SAT
7 SUN

Later's internal representation of weekdays are:

1 SUN
2 MON
3 TUE
4 WED
5 THU
6 FRI
7 SAT

So far so good. The test title

        it('should parse 7 as Sunday', function() {
            var p = parse('* * * * * 7', true);
            p.schedules[0].should.eql({d: [1]});
        });

Right now, Later parses '* * * * * 7' as Saturday which is incorrect.