diff --git a/administrator/components/com_admin/sql/updates/mysql/4.0.0-2018-08-01.sql b/administrator/components/com_admin/sql/updates/mysql/4.0.0-2018-08-01.sql
new file mode 100644
index 0000000000000..72a50731c9444
--- /dev/null
+++ b/administrator/components/com_admin/sql/updates/mysql/4.0.0-2018-08-01.sql
@@ -0,0 +1,8 @@
+ALTER TABLE `#__ucm_content` MODIFY `core_created_time` datetime NOT NULL;
+ALTER TABLE `#__ucm_content` MODIFY `core_modified_time` datetime NOT NULL;
+
+ALTER TABLE `#__ucm_content` MODIFY `core_publish_up` datetime NULL DEFAULT NULL;
+ALTER TABLE `#__ucm_content` MODIFY `core_publish_down` datetime NULL DEFAULT NULL;
+ALTER TABLE `#__ucm_content` MODIFY `core_checked_out_time` datetime NULL DEFAULT NULL;
+
+ALTER TABLE `#__ucm_history` MODIFY `save_date` datetime NOT NULL;
diff --git a/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-09-14.sql b/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-09-14.sql
index eec96a1aa255d..655d9ac166366 100644
--- a/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-09-14.sql
+++ b/administrator/components/com_admin/sql/updates/mysql/4.0.0-2019-09-14.sql
@@ -1,7 +1,26 @@
+ALTER TABLE `#__content` MODIFY `created` datetime NOT NULL;
+ALTER TABLE `#__content` MODIFY `modified` datetime NOT NULL;
+
 ALTER TABLE `#__content` MODIFY `publish_up` datetime NULL DEFAULT NULL;
 ALTER TABLE `#__content` MODIFY `publish_down` datetime NULL DEFAULT NULL;
 ALTER TABLE `#__content` MODIFY `checked_out_time` datetime NULL DEFAULT NULL;
 
+UPDATE `#__content` SET `modified` = `created` WHERE `modified` = '0000-00-00 00:00:00';
+
 UPDATE `#__content` SET `publish_up` = NULL WHERE `publish_up` = '0000-00-00 00:00:00';
 UPDATE `#__content` SET `publish_down` = NULL WHERE `publish_down` = '0000-00-00 00:00:00';
 UPDATE `#__content` SET `checked_out_time` = NULL WHERE `checked_out_time` = '0000-00-00 00:00:00';
+
+UPDATE `#__ucm_content` SET `core_modified_time` = `core_created_time`
+ WHERE `core_type_alias` = 'com_content.article'
+   AND `core_modified_time` = '0000-00-00 00:00:00';
+
+UPDATE `#__ucm_content` SET `core_publish_up` = NULL
+ WHERE `core_type_alias` = 'com_content.article'
+   AND `core_publish_up` = '0000-00-00 00:00:00';
+UPDATE `#__ucm_content` SET `core_publish_down` = NULL
+ WHERE `core_type_alias` = 'com_content.article'
+   AND `core_publish_down` = '0000-00-00 00:00:00';
+UPDATE `#__ucm_content` SET `core_checked_out_time` = NULL
+ WHERE `core_type_alias` = 'com_content.article'
+   AND `core_checked_out_time` = '0000-00-00 00:00:00';
diff --git a/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2018-08-01.sql b/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2018-08-01.sql
new file mode 100644
index 0000000000000..e0958379aa79f
--- /dev/null
+++ b/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2018-08-01.sql
@@ -0,0 +1,14 @@
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_created_time" DROP DEFAULT;
+
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_modified_time" DROP DEFAULT;
+
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_publish_up" DROP NOT NULL;
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_publish_up" DROP DEFAULT;
+
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_publish_down" DROP NOT NULL;
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_publish_down" DROP DEFAULT;
+
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_checked_out_time" DROP NOT NULL;
+ALTER TABLE "#__ucm_content" ALTER COLUMN "core_checked_out_time" DROP DEFAULT;
+
+ALTER TABLE "#__ucm_history" ALTER COLUMN "save_date" DROP DEFAULT;
diff --git a/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-09-14.sql b/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-09-14.sql
index 8ae870d3d45b8..252696d2d5b11 100644
--- a/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-09-14.sql
+++ b/administrator/components/com_admin/sql/updates/postgresql/4.0.0-2019-09-14.sql
@@ -1,3 +1,7 @@
+ALTER TABLE "#__content" ALTER COLUMN "created" DROP DEFAULT;
+
+ALTER TABLE "#__content" ALTER COLUMN "modified" DROP DEFAULT;
+
 ALTER TABLE "#__content" ALTER COLUMN "publish_up" DROP NOT NULL;
 ALTER TABLE "#__content" ALTER COLUMN "publish_up" DROP DEFAULT;
 
@@ -10,3 +14,13 @@ ALTER TABLE "#__content" ALTER COLUMN "checked_out_time" DROP DEFAULT;
 UPDATE "#__content" SET "publish_up" = NULL WHERE "publish_up" = '1970-01-01 00:00:00';
 UPDATE "#__content" SET "publish_down" = NULL WHERE "publish_down" = '1970-01-01 00:00:00';
 UPDATE "#__content" SET "checked_out_time" = NULL WHERE "checked_out_time" = '1970-01-01 00:00:00';
+
+UPDATE "#__ucm_content" SET "core_publish_up" = NULL
+ WHERE "core_type_alias" = 'com_content.article'
+   AND "core_publish_up" = '1970-01-01 00:00:00';
+UPDATE "#__ucm_content" SET "core_publish_down" = NULL
+ WHERE "core_type_alias" = 'com_content.article'
+   AND "core_publish_down" = '1970-01-01 00:00:00';
+UPDATE "#__ucm_content" SET "core_checked_out_time" = NULL
+ WHERE "core_type_alias" = 'com_content.article'
+   AND "core_checked_out_time" = '1970-01-01 00:00:00';
diff --git a/components/com_content/Model/ArticleModel.php b/components/com_content/Model/ArticleModel.php
index a72a9184bad30..7dbbe71b47244 100644
--- a/components/com_content/Model/ArticleModel.php
+++ b/components/com_content/Model/ArticleModel.php
@@ -100,9 +100,7 @@ public function getItem($pk = null)
 						$this->getState(
 							'item.select', 'a.id, a.asset_id, a.title, a.alias, a.introtext, a.fulltext, ' .
 							'a.state, a.catid, a.created, a.created_by, a.created_by_alias, ' .
-							// Use created if modified is 0
-							'CASE WHEN a.modified = ' . $db->quote($db->getNullDate()) . ' THEN a.created ELSE a.modified END as modified, ' .
-							'a.modified_by, a.checked_out, a.checked_out_time, a.publish_up, a.publish_down, ' .
+							'a.modified, a.modified_by, a.checked_out, a.checked_out_time, a.publish_up, a.publish_down, ' .
 							'a.images, a.urls, a.attribs, a.version, a.ordering, ' .
 							'a.metakey, a.metadesc, a.access, a.hits, a.metadata, a.featured, a.language'
 						)
diff --git a/components/com_content/Model/ArticlesModel.php b/components/com_content/Model/ArticlesModel.php
index 9379256aa9939..2bcbff921d563 100644
--- a/components/com_content/Model/ArticlesModel.php
+++ b/components/com_content/Model/ArticlesModel.php
@@ -207,9 +207,7 @@ protected function getListQuery()
 				// If category is not published then force 0
 				'CASE WHEN c.published = 2 AND ws.condition > 0 THEN ' . (int) ContentComponent::CONDITION_ARCHIVED .
 				' WHEN c.published != 1 THEN ' . (int) ContentComponent::CONDITION_UNPUBLISHED . ' ELSE ws.condition END as state,' .
-				// Use created if modified is 0
-				'CASE WHEN a.modified = ' . $db->quote($db->getNullDate()) . ' THEN a.created ELSE a.modified END as modified, ' .
-				'a.modified_by, uam.name as modified_by_name,' .
+				'a.modified, a.modified_by, uam.name as modified_by_name,' .
 				// Use created if publish_up is 0
 				'CASE WHEN a.publish_up IS NULL THEN a.created ELSE a.publish_up END as publish_up,' .
 				'a.publish_down, a.images, a.urls, a.attribs, a.metadata, a.metakey, a.metadesc, a.access, ' .
@@ -467,7 +465,6 @@ function ($data) use ($db)
 		}
 
 		// Define null and now dates
-		$nullDate = $db->quote($db->getNullDate());
 		$nowDate  = $db->quote(Factory::getDate()->toSql());
 
 		// Filter by start and end dates.
@@ -484,8 +481,8 @@ function ($data) use ($db)
 		switch ($dateFiltering)
 		{
 			case 'range':
-				$startDateRange = $db->quote($this->getState('filter.start_date_range', $nullDate));
-				$endDateRange   = $db->quote($this->getState('filter.end_date_range', $nullDate));
+				$startDateRange = $db->quote($this->getState('filter.start_date_range'));
+				$endDateRange   = $db->quote($this->getState('filter.end_date_range'));
 				$query->where(
 					'(' . $dateField . ' >= ' . $startDateRange . ' AND ' . $dateField .
 					' <= ' . $endDateRange . ')'
diff --git a/installation/sql/mysql/joomla.sql b/installation/sql/mysql/joomla.sql
index 490e66cead243..c0ad46e8a378f 100644
--- a/installation/sql/mysql/joomla.sql
+++ b/installation/sql/mysql/joomla.sql
@@ -346,10 +346,10 @@ CREATE TABLE IF NOT EXISTS `#__content` (
   `fulltext` mediumtext NOT NULL,
   `state` tinyint(3) NOT NULL DEFAULT 0,
   `catid` int(10) unsigned NOT NULL DEFAULT 0,
-  `created` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
+  `created` datetime NOT NULL,
   `created_by` int(10) unsigned NOT NULL DEFAULT 0,
   `created_by_alias` varchar(255) NOT NULL DEFAULT '',
-  `modified` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
+  `modified` datetime NOT NULL,
   `modified_by` int(10) unsigned NOT NULL DEFAULT 0,
   `checked_out` int(10) unsigned NOT NULL DEFAULT 0,
   `checked_out_time` datetime NULL DEFAULT NULL,
@@ -1863,7 +1863,7 @@ CREATE TABLE IF NOT EXISTS `#__ucm_content` (
   `core_alias` varchar(400) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL DEFAULT '',
   `core_body` mediumtext NOT NULL DEFAULT '',
   `core_state` tinyint(1) NOT NULL DEFAULT 0,
-  `core_checked_out_time` varchar(255) NOT NULL DEFAULT '0000-00-00 00:00:00',
+  `core_checked_out_time` datetime,
   `core_checked_out_user_id` int(10) unsigned NOT NULL DEFAULT 0,
   `core_access` int(10) unsigned NOT NULL DEFAULT 0,
   `core_params` text NOT NULL DEFAULT '',
@@ -1871,12 +1871,12 @@ CREATE TABLE IF NOT EXISTS `#__ucm_content` (
   `core_metadata` varchar(2048) NOT NULL DEFAULT '' COMMENT 'JSON encoded metadata properties.',
   `core_created_user_id` int(10) unsigned NOT NULL DEFAULT 0,
   `core_created_by_alias` varchar(255) NOT NULL DEFAULT '',
-  `core_created_time` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
+  `core_created_time` datetime NOT NULL,
   `core_modified_user_id` int(10) unsigned NOT NULL DEFAULT 0 COMMENT 'Most recent user that modified',
-  `core_modified_time` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
+  `core_modified_time` datetime NOT NULL,
   `core_language` char(7) NOT NULL DEFAULT '',
-  `core_publish_up` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
-  `core_publish_down` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
+  `core_publish_up` datetime,
+  `core_publish_down` datetime,
   `core_content_item_id` int(10) unsigned NOT NULL DEFAULT 0 COMMENT 'ID from the individual type table',
   `asset_id` int(10) unsigned NOT NULL DEFAULT 0 COMMENT 'FK to the #__assets table.',
   `core_images` text NOT NULL DEFAULT '',
@@ -1914,7 +1914,7 @@ CREATE TABLE IF NOT EXISTS `#__ucm_history` (
   `ucm_item_id` int(10) unsigned NOT NULL,
   `ucm_type_id` int(10) unsigned NOT NULL,
   `version_note` varchar(255) NOT NULL DEFAULT '' COMMENT 'Optional version name',
-  `save_date` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
+  `save_date` datetime NOT NULL,
   `editor_user_id` int(10) unsigned NOT NULL DEFAULT 0,
   `character_count` int(10) unsigned NOT NULL DEFAULT 0 COMMENT 'Number of characters in this version.',
   `sha1_hash` varchar(50) NOT NULL DEFAULT '' COMMENT 'SHA1 hash of the version_data column.',
diff --git a/installation/sql/postgresql/joomla.sql b/installation/sql/postgresql/joomla.sql
index fc8b2e60d1a1e..1e1c60f061970 100644
--- a/installation/sql/postgresql/joomla.sql
+++ b/installation/sql/postgresql/joomla.sql
@@ -351,10 +351,10 @@ CREATE TABLE IF NOT EXISTS "#__content" (
   "fulltext" text NOT NULL,
   "state" smallint DEFAULT 0 NOT NULL,
   "catid" bigint DEFAULT 0 NOT NULL,
-  "created" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
+  "created" timestamp without time zone NOT NULL,
   "created_by" bigint DEFAULT 0 NOT NULL,
   "created_by_alias" varchar(255) DEFAULT '' NOT NULL,
-  "modified" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
+  "modified" timestamp without time zone NOT NULL,
   "modified_by" bigint DEFAULT 0 NOT NULL,
   "checked_out" bigint DEFAULT 0 NOT NULL,
   "checked_out_time" timestamp without time zone,
@@ -1855,7 +1855,7 @@ CREATE TABLE IF NOT EXISTS "#__ucm_content" (
   "core_alias" varchar(255) DEFAULT '' NOT NULL,
   "core_body" text NOT NULL DEFAULT '',
   "core_state" smallint DEFAULT 0 NOT NULL,
-  "core_checked_out_time" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
+  "core_checked_out_time" timestamp without time zone,
   "core_checked_out_user_id" bigint DEFAULT 0 NOT NULL,
   "core_access" bigint DEFAULT 0 NOT NULL,
   "core_params" text DEFAULT '' NOT NULL,
@@ -1863,12 +1863,12 @@ CREATE TABLE IF NOT EXISTS "#__ucm_content" (
   "core_metadata" text DEFAULT '' NOT NULL,
   "core_created_user_id" bigint DEFAULT 0 NOT NULL,
   "core_created_by_alias" varchar(255) DEFAULT '' NOT NULL,
-  "core_created_time" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
+  "core_created_time" timestamp without time zone NOT NULL,
   "core_modified_user_id" bigint DEFAULT 0 NOT NULL,
-  "core_modified_time" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
+  "core_modified_time" timestamp without time zone NOT NULL,
   "core_language" varchar(7) DEFAULT '' NOT NULL,
-  "core_publish_up" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
-  "core_publish_down" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
+  "core_publish_up" timestamp without time zone,
+  "core_publish_down" timestamp without time zone,
   "core_content_item_id" bigint DEFAULT 0 NOT NULL,
   "asset_id" bigint DEFAULT 0 NOT NULL,
   "core_images" text DEFAULT '' NOT NULL,
@@ -1905,7 +1905,7 @@ CREATE TABLE IF NOT EXISTS "#__ucm_history" (
   "ucm_item_id" integer NOT NULL,
   "ucm_type_id" integer NOT NULL,
   "version_note" varchar(255) NOT NULL DEFAULT '',
-  "save_date" timestamp with time zone NOT NULL DEFAULT '1970-01-01 00:00:00',
+  "save_date" timestamp with time zone NOT NULL,
   "editor_user_id" integer  NOT NULL DEFAULT 0,
   "character_count" integer  NOT NULL DEFAULT 0,
   "sha1_hash" varchar(50) NOT NULL DEFAULT '',
diff --git a/libraries/src/Table/CoreContent.php b/libraries/src/Table/CoreContent.php
index 37ac1628e726a..1ab00c70c212f 100644
--- a/libraries/src/Table/CoreContent.php
+++ b/libraries/src/Table/CoreContent.php
@@ -26,6 +26,14 @@
  */
 class CoreContent extends Table
 {
+	/**
+	 * Indicates that columns fully support the NULL value in the database
+	 *
+	 * @var    boolean
+	 * @since  __DEPLOY_VERSION__
+	 */
+	protected $_supportNullValue = true;
+
 	/**
 	 * Constructor
 	 *
@@ -245,7 +253,7 @@ public function deleteByContentId($contentItemId = null, $typeAlias = null)
 	 *
 	 * @since   3.1
 	 */
-	public function store($updateNulls = false)
+	public function store($updateNulls = true)
 	{
 		$date = Factory::getDate();
 		$user = Factory::getUser();
@@ -271,6 +279,11 @@ public function store($updateNulls = false)
 				$this->core_created_user_id = $user->get('id');
 			}
 
+			if (!(int) $this->core_modified_time)
+			{
+				$this->core_modified_time = $this->core_created_time;
+			}
+
 			$isNew = true;
 		}
 
@@ -296,7 +309,7 @@ public function store($updateNulls = false)
 	 *
 	 * @since   3.1
 	 */
-	protected function storeUcmBase($updateNulls = false, $isNew = false)
+	protected function storeUcmBase($updateNulls = true, $isNew = false)
 	{
 		// Store the ucm_base row
 		$db         = $this->getDbo();
diff --git a/plugins/content/pagenavigation/pagenavigation.php b/plugins/content/pagenavigation/pagenavigation.php
index 6193f735efeb1..d33adbaf2ab08 100644
--- a/plugins/content/pagenavigation/pagenavigation.php
+++ b/plugins/content/pagenavigation/pagenavigation.php
@@ -53,7 +53,6 @@ public function onContentBeforeDisplay($context, &$row, &$params, $page = 0)
 			$db       = Factory::getDbo();
 			$user     = Factory::getUser();
 			$lang     = Factory::getLanguage();
-			$nullDate = $db->getNullDate();
 
 			$date = Factory::getDate();
 			$now  = $date->toSql();
@@ -253,7 +252,7 @@ private static function getQueryDate($orderDate)
 		{
 			// Use created if modified is not set
 			case 'modified' :
-				$queryDate = ' CASE WHEN a.modified = ' . $db->quote($db->getNullDate()) . ' THEN a.created ELSE a.modified END';
+				$queryDate = ' a.modified';
 				break;
 
 			// Use created if publish_up is not set