Why is 12/31/1990 the only available Post Date?

When creating an export, users will have the option to select the desired Post Date from the dropdown menu. This will list all of the available Post Periods for the selected export and hierarchy. 

If an export does not need reference Post Periods when determining which data to extract, the date '12/31/1990' is used as a placeholder. 

This is often seen with standard and customer User Defined Exports. 

To learn more about export contents and requirements, check out the Standard Interface Guide:

Standard Interface Guide