Hi -- date formats prior to 2016 are showing up completely wrong (day/month wrong, and all years as 1900, also wrong). 

I'm attaching our source spreadsheet. The column we use for dates in the WPDT is "Date General." Date has been formatted as "Text."

In the past we had a similar problem and were provided with this code workaround, which is no longer working: 

THIS IS THE MODIFIED VERSION THAT USED TO FIX THE DATE PROBLEM (wp-content/plugins/wpdatatables/source/class.date.wpdatacolumn.php):

<?php

/**
 * Class IntColumn is a child column class used
 * to describe columns with float numeric content
 *
 * @author Alexander Gilmanov
 *
 * @since May 2012
 */

class DateWDTColumn extends WDTColumn {
    
    protected $_jsDataType = 'date';
    protected $_dataType = 'date';
    
    public function __construct( $properties = array () ) {
        parent::__construct( $properties );
        $this->_dataType = 'date';
        
        switch(get_option('wdtDateFormat')){
            case 'd/m/Y':
            case 'd.m.Y':
            case 'd-m-Y':
            case 'd.m.y':
            case 'd-m-y':
                $this->_jsDataType = 'date-eu';
                break;
            case 'd-m-Y':
                $this->_jsDataType = 'date-dd-mmm-yyyy';
                break;
        }
                
    }
    
    public function prepareCellOutput( $content ) {
        if(!is_array($content)){
            if( !empty($content) && ( $content != '0000-00-00' ) ){
                $date = new DateTime($content);
                $formattedValue = $date->format(get_option('wdtDateFormat'));
            }else{
                $formattedValue = '';
            }
        }else{
            $date = new DateTime($content);
            $formattedValue = $date->format(get_option('wdtDateFormat'));
        }
        $formattedValue = apply_filters('wpdatatables_filter_date_cell', $formattedValue);
        return $formattedValue;
    }
    
    public function getGoogleChartColumnType(){
        return 'date';
    }
    
}

?>

I just attached screenshots, but they looked totally creepy and not what I grabbed! What is going on over there?

I deleted the screenshots as it looked like some sort of spyware was looking at my computer! They were not the screenshots I had captured, but rather other views of my computer's windows and settings. Really creepy. Made me suspicious, and for that reason I am not comfortable providing my login to your company. 

However, WPDatatables is still the best solution I have found for our needs, so for now we will keep using it. Hopefully that situation was an anomaly, and we can trust WPDT!?