diff --git a/src/administrator/components/com_weblinks/Table/WeblinkTable.php b/src/administrator/components/com_weblinks/Table/WeblinkTable.php
index 4e08601..57166ac 100644
--- a/src/administrator/components/com_weblinks/Table/WeblinkTable.php
+++ b/src/administrator/components/com_weblinks/Table/WeblinkTable.php
@@ -18,6 +18,14 @@ defined('_JEXEC') or die;
  */
 class WeblinkTable extends \JTable
 {
+	/**
+	 * Indicates that columns fully support the NULL value in the database
+	 *
+	 * @var    boolean
+	 * @since  4.0.0
+	 */
+	protected $_supportNullValue = true;
+
 	/**
 	 * Ensure the params and metadata in json encoded in the bind method
 	 *
@@ -56,17 +64,16 @@ class WeblinkTable extends \JTable
 	 *
 	 * @since   1.6
 	 */
-	public function store($updateNulls = false)
+	public function store($updateNulls = true)
 	{
-		$date = \JFactory::getDate();
+		$date = \JFactory::getDate()->toSql();
 		$user = \JFactory::getUser();
 
-		$this->modified = $date->toSql();
-
 		if ($this->id)
 		{
 			// Existing item
 			$this->modified_by = $user->id;
+			$this->modified    = $date;
 		}
 		else
 		{
@@ -74,25 +81,35 @@ class WeblinkTable extends \JTable
 			// so we don't touch either of these if they are set.
 			if (!(int) $this->created)
 			{
-				$this->created = $date->toSql();
+				$this->created = $date;
 			}
 
 			if (empty($this->created_by))
 			{
 				$this->created_by = $user->id;
 			}
+
+			if (!(int) $this->modified)
+			{
+				$this->modified = $date;
+			}
+
+			if (empty($this->modified_by))
+			{
+				$this->modified_by = $user->id;
+			}
 		}
 
-		// Set publish_up to null date if not set
+		// Set publish_up to null if not set
 		if (!$this->publish_up)
 		{
-			$this->publish_up = $this->getDbo()->getNullDate();
+			$this->publish_up = null;
 		}
 
-		// Set publish_down to null date if not set
+		// Set publish_down to null if not set
 		if (!$this->publish_down)
 		{
-			$this->publish_down = $this->getDbo()->getNullDate();
+			$this->publish_down = null;
 		}
 
 		// Verify that the alias is unique
@@ -168,7 +185,7 @@ class WeblinkTable extends \JTable
 		}
 
 		// Check the publish down date is not earlier than publish up.
-		if ($this->publish_down > $db->getNullDate() && $this->publish_down < $this->publish_up)
+		if ((int) $this->publish_down > 0 && $this->publish_down < $this->publish_up)
 		{
 			$this->setError(\JText::_('JGLOBAL_START_PUBLISH_AFTER_FINISH'));
 
diff --git a/src/administrator/components/com_weblinks/script.php b/src/administrator/components/com_weblinks/script.php
index b43cae4..9f48e20 100644
--- a/src/administrator/components/com_weblinks/script.php
+++ b/src/administrator/components/com_weblinks/script.php
@@ -44,7 +44,7 @@ class Com_WeblinksInstallerScript
 			$category->metadesc = '';
 			$category->metakey = '';
 			$category->language = '*';
-			$category->checked_out_time = JFactory::getDbo()->getNullDate();
+			$category->checked_out_time = null;
 			$category->version = 1;
 			$category->hits = 0;
 			$category->modified_user_id = 0;
diff --git a/src/components/com_weblinks/models/category.php b/src/components/com_weblinks/models/category.php
index 9378226..855a6fa 100644
--- a/src/components/com_weblinks/models/category.php
+++ b/src/components/com_weblinks/models/category.php
@@ -163,13 +163,12 @@ class WeblinksModelCategory extends JModelList
 		$query->where('a.state != -2');
 
 		// Filter by start and end dates.
-		$nullDate = $db->quote($db->getNullDate());
 		$nowDate  = $db->quote(JFactory::getDate()->toSql());
 
 		if ($this->getState('filter.publish_date'))
 		{
-			$query->where('(a.publish_up = ' . $nullDate . ' OR a.publish_up <= ' . $nowDate . ')')
-				->where('(a.publish_down = ' . $nullDate . ' OR a.publish_down >= ' . $nowDate . ')');
+			$query->where('(a.publish_up IS NULL OR a.publish_up <= ' . $nowDate . ')')
+				->where('(a.publish_down IS NULL OR a.publish_down >= ' . $nowDate . ')');
 		}
 
 		// Filter by language
diff --git a/src/components/com_weblinks/models/weblink.php b/src/components/com_weblinks/models/weblink.php
index 3c6ce13..5754ca5 100644
--- a/src/components/com_weblinks/models/weblink.php
+++ b/src/components/com_weblinks/models/weblink.php
@@ -110,13 +110,12 @@ class WeblinksModelWeblink extends JModelItem
 				if ((!$user->authorise('core.edit.state', 'com_weblinks')) && (!$user->authorise('core.edit', 'com_weblinks')))
 				{
 					// Filter by start and end dates.
-					$nullDate = $db->quote($db->getNullDate());
 					$date = JFactory::getDate();
 
 					$nowDate = $db->quote($date->toSql());
 
-					$query->where('(a.publish_up = ' . $nullDate . ' OR a.publish_up <= ' . $nowDate . ')')
-						->where('(a.publish_down = ' . $nullDate . ' OR a.publish_down >= ' . $nowDate . ')');
+					$query->where('(a.publish_up IS NULL OR a.publish_up <= ' . $nowDate . ')')
+						->where('(a.publish_down IS NULL OR a.publish_down >= ' . $nowDate . ')');
 				}
 
 				// Filter by published state.