Last modified: 2013-10-09 17:24:17 UTC
if you enter e.g. "1.1.2" as date, it will be evaluated as "January 12, 30" after a reload of the page.
I just tested this here: https://www.wikidata.org/w/index.php?title=Q4115189&oldid=75307099 Seems to be working fine now.