When you install the Historical Dates Add-on the formats of the dates are altered to allow for dates dating back to as far as the year 1000. This is made possible by the add-on by re-formatting the dates before they ever get stored in the database.
Because of this, if you were previously using either the free or pro version of Timeline Express and had set-up your announcements before you installed the add-on, you’ll just need to update your announcements so that they get stored in the database in the correct format.
You can do this by heading back into the announcements that are displaying this warning, re-setting the date (if need be), and re-saving the announcement by clicking on ‘Update’.
If you don’t have any of our add-ons installed, please reach out to our support staff for personal assistance.