Test Dates

First go automatic.

1. Now set year 11- that worked
2. Now try 20 Also worked
3. Go for 60 - no it did not like it so it is still 20
4. Maybe 40 - no good
5. So 30 - no
6. Must be 29 - Yes Yes 
7. So I think 2099 - Of course it works
8. Maybe 2199 -No problem
9. Now 70 it will work - it did
10. But 69 will not - No it does not like it
11. Maybe 1969 - No
12. It is mad but 1869?- No
13. 1971 just to move it - Yes ok
14. 1970 should work - Yes

So the conclusion:

1. You cannot date a post before 1970
2. You may date a post anytime in the future (well at least 2199)
3. If you enter from 70-99 it will assume 19nn.
4. If you enter from 00-29 it will assume 20nn.
5. you can enter any year from 1970 onwards as four didgits.