Can’t save dates before 2007

The timepicker used in the plugin displays years between -10 and +10 from this year. I can type older years into text field but when I click Publish, the plugin does not save any value into its post meta post-event-date. I go to phpMyAdmin and insert the timestamp manually, then the years are displayed in the timeline. But you definitely need to look after this issue.
Maybe you can add a setting to admin page, so we can add a year range manually.