diff --git a/administrator/components/com_admin/sql/updates/mysql/3.7.0-2017-03-03.sql b/administrator/components/com_admin/sql/updates/mysql/3.7.0-2017-03-03.sql
new file mode 100644
index 0000000000000..ada236b5889cf
--- /dev/null
+++ b/administrator/components/com_admin/sql/updates/mysql/3.7.0-2017-03-03.sql
@@ -0,0 +1,5 @@
+ALTER TABLE `#__languages` MODIFY `asset_id` int(10) unsigned NOT NULL DEFAULT 0;
+ALTER TABLE `#__menu_types` MODIFY `asset_id` int(10) unsigned NOT NULL DEFAULT 0;
+
+ALTER TABLE  `#__content` MODIFY `xreference` varchar(50) NOT NULL DEFAULT '';
+ALTER TABLE  `#__newsfeeds` MODIFY `xreference` varchar(50) NOT NULL DEFAULT '';
diff --git a/administrator/components/com_admin/sql/updates/postgresql/3.7.0-2017-03-03.sql b/administrator/components/com_admin/sql/updates/postgresql/3.7.0-2017-03-03.sql
new file mode 100644
index 0000000000000..806caf88b09f8
--- /dev/null
+++ b/administrator/components/com_admin/sql/updates/postgresql/3.7.0-2017-03-03.sql
@@ -0,0 +1,5 @@
+ALTER TABLE "#__extensions" ALTER COLUMN "custom_data" DROP DEFAULT;
+ALTER TABLE "#__extensions" ALTER COLUMN "system_data" DROP DEFAULT;
+ALTER TABLE "#__updates" ALTER COLUMN "data" DROP DEFAULT;
+
+ALTER TABLE "#__newsfeeds" ALTER COLUMN "xreference" SET DEFAULT '';
diff --git a/administrator/components/com_admin/sql/updates/sqlazure/3.7.0-2017-03-03.sql b/administrator/components/com_admin/sql/updates/sqlazure/3.7.0-2017-03-03.sql
new file mode 100644
index 0000000000000..94af5bdc08153
--- /dev/null
+++ b/administrator/components/com_admin/sql/updates/sqlazure/3.7.0-2017-03-03.sql
@@ -0,0 +1,31 @@
+CREATE PROCEDURE "#removeDefault"
+(
+	@table NVARCHAR(100),
+	@column NVARCHAR(100)
+)
+AS
+BEGIN
+	DECLARE @constraintName AS nvarchar(100)
+	DECLARE @constraintQuery AS nvarchar(1000)
+	SELECT @constraintName = name FROM sys.default_constraints
+		WHERE parent_object_id = object_id(@table)
+		AND parent_column_id = columnproperty(object_id(@table), @column, 'ColumnId')
+	SET @constraintQuery = 'ALTER TABLE [' + @table + '] DROP CONSTRAINT [' + @constraintName + ']'
+	EXECUTE sp_executesql @constraintQuery
+END;
+
+EXECUTE "#removeDefault" "#__extensions", 'system_data';
+EXECUTE "#removeDefault" "#__updates", 'data';
+
+ALTER TABLE "#__content" ADD DEFAULT ('') FOR "xreference";
+ALTER TABLE "#__newsfeeds" ADD DEFAULT ('') FOR "xreference";
+
+-- Delete wrong unique index
+DROP INDEX "idx_access" ON "#__languages";
+
+-- Add missing unique index
+ALTER TABLE "#__languages" ADD CONSTRAINT "#__languages$idx_langcode" UNIQUE ("lang_code") ON [PRIMARY];
+
+-- Add missing index keys
+CREATE INDEX "idx_access" ON "#__languages" ("access");
+CREATE INDEX "idx_ordering" ON "#__languages" ("ordering");
diff --git a/administrator/components/com_installer/models/discover.php b/administrator/components/com_installer/models/discover.php
index 8b8f6bc496274..1403e816f4e93 100644
--- a/administrator/components/com_installer/models/discover.php
+++ b/administrator/components/com_installer/models/discover.php
@@ -166,6 +166,7 @@ public function discover()
 			if (!array_key_exists($key, $extensions))
 			{
 				// Put it into the table
+				$result->check();
 				$result->store();
 			}
 		}
diff --git a/administrator/components/com_installer/models/languages.php b/administrator/components/com_installer/models/languages.php
index fc01a9a946186..2a6611c75a165 100644
--- a/administrator/components/com_installer/models/languages.php
+++ b/administrator/components/com_installer/models/languages.php
@@ -143,14 +143,17 @@ protected function getLanguages()
 			$languages[$language->name] = $language;
 		}
 
+		// Workaround for php 5.3
+		$that = $this;
+
 		// Sort the array by value of subarray
 		usort(
 			$languages,
-			function($a, $b)
+			function($a, $b) use ($that)
 			{
-				$ordering = $this->getState('list.ordering');
+				$ordering = $that->getState('list.ordering');
 
-				if (strtolower($this->getState('list.direction')) === 'asc')
+				if (strtolower($that->getState('list.direction')) === 'asc')
 				{
 					return StringHelper::strcmp($a->$ordering, $b->$ordering);
 				}
diff --git a/installation/sql/mysql/joomla.sql b/installation/sql/mysql/joomla.sql
index e0228bd9655d3..4e14962548424 100644
--- a/installation/sql/mysql/joomla.sql
+++ b/installation/sql/mysql/joomla.sql
@@ -343,7 +343,7 @@ CREATE TABLE IF NOT EXISTS `#__content` (
   `metadata` text NOT NULL,
   `featured` tinyint(3) unsigned NOT NULL DEFAULT 0 COMMENT 'Set if article is featured.',
   `language` char(7) NOT NULL COMMENT 'The language code for the article.',
-  `xreference` varchar(50) NOT NULL COMMENT 'A reference to enable linkages to external data sets.',
+  `xreference` varchar(50) NOT NULL DEFAULT '' COMMENT 'A reference to enable linkages to external data sets.',
   PRIMARY KEY (`id`),
   KEY `idx_access` (`access`),
   KEY `idx_checkout` (`checked_out`),
@@ -655,7 +655,7 @@ INSERT INTO `#__extensions` (`extension_id`, `package_id`, `name`, `type`, `elem
 
 CREATE TABLE IF NOT EXISTS `#__fields` (
   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
-  `asset_id` int(10) NOT NULL DEFAULT 0,
+  `asset_id` int(10) unsigned NOT NULL DEFAULT 0,
   `context` varchar(255) NOT NULL DEFAULT '',
   `group_id` int(10) NOT NULL DEFAULT 0,
   `title` varchar(255) NOT NULL DEFAULT '',
@@ -707,7 +707,7 @@ CREATE TABLE `#__fields_categories` (
 
 CREATE TABLE IF NOT EXISTS `#__fields_groups` (
   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
-  `asset_id` int(10) NOT NULL DEFAULT 0,
+  `asset_id` int(10) unsigned NOT NULL DEFAULT 0,
   `context` varchar(255) NOT NULL DEFAULT '',
   `title` varchar(255) NOT NULL DEFAULT '',
   `note` varchar(255) NOT NULL DEFAULT '',
@@ -1307,7 +1307,7 @@ CREATE TABLE IF NOT EXISTS `#__finder_types` (
 
 CREATE TABLE IF NOT EXISTS `#__languages` (
   `lang_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
-  `asset_id` int(11) NOT NULL,
+  `asset_id` int(10) unsigned NOT NULL DEFAULT 0,
   `lang_code` char(7) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL,
   `title` varchar(50) NOT NULL,
   `title_native` varchar(50) NOT NULL,
@@ -1411,7 +1411,7 @@ INSERT INTO `#__menu` (`id`, `menutype`, `title`, `alias`, `note`, `path`, `link
 
 CREATE TABLE IF NOT EXISTS `#__menu_types` (
   `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
-  `asset_id` int(11) NOT NULL,
+  `asset_id` int(10) unsigned NOT NULL DEFAULT 0,
   `menutype` varchar(24) NOT NULL,
   `title` varchar(48) NOT NULL,
   `description` varchar(255) NOT NULL DEFAULT '',
@@ -1577,7 +1577,7 @@ CREATE TABLE IF NOT EXISTS `#__newsfeeds` (
   `metakey` text NOT NULL,
   `metadesc` text NOT NULL,
   `metadata` text NOT NULL,
-  `xreference` varchar(50) NOT NULL COMMENT 'A reference to enable linkages to external data sets.',
+  `xreference` varchar(50) NOT NULL DEFAULT '' COMMENT 'A reference to enable linkages to external data sets.',
   `publish_up` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
   `publish_down` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
   `description` text NOT NULL,
diff --git a/installation/sql/postgresql/joomla.sql b/installation/sql/postgresql/joomla.sql
index d32dba6a042c1..04a745b3cb8f4 100644
--- a/installation/sql/postgresql/joomla.sql
+++ b/installation/sql/postgresql/joomla.sql
@@ -479,8 +479,8 @@ CREATE TABLE "#__extensions" (
   "protected" smallint DEFAULT 0 NOT NULL,
   "manifest_cache" text NOT NULL,
   "params" text NOT NULL,
-  "custom_data" text DEFAULT '' NOT NULL,
-  "system_data" text DEFAULT '' NOT NULL,
+  "custom_data" text NOT NULL,
+  "system_data" text NOT NULL,
   "checked_out" integer DEFAULT 0 NOT NULL,
   "checked_out_time" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
   "ordering" bigint DEFAULT 0,
@@ -1548,7 +1548,7 @@ CREATE TABLE "#__newsfeeds" (
   "metakey" text NOT NULL,
   "metadesc" text NOT NULL,
   "metadata" text NOT NULL,
-  "xreference" varchar(50) NOT NULL,
+  "xreference" varchar(50) NOT NULL DEFAULT '',
   "publish_up" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
   "publish_down" timestamp without time zone DEFAULT '1970-01-01 00:00:00' NOT NULL,
   "description" text NOT NULL,
@@ -1863,7 +1863,7 @@ CREATE TABLE "#__updates" (
   "folder" varchar(20) DEFAULT '',
   "client_id" smallint DEFAULT 0,
   "version" varchar(32) DEFAULT '',
-  "data" text DEFAULT '' NOT NULL,
+  "data" text NOT NULL,
   "detailsurl" text NOT NULL,
   "infourl" text NOT NULL,
   "extra_query" varchar(1000) DEFAULT '',
diff --git a/installation/sql/sqlazure/joomla.sql b/installation/sql/sqlazure/joomla.sql
index 576abce7d12f1..af0a014762cda 100644
--- a/installation/sql/sqlazure/joomla.sql
+++ b/installation/sql/sqlazure/joomla.sql
@@ -491,7 +491,7 @@ CREATE TABLE "#__content" (
   "metadata" nvarchar(max) NOT NULL,
   "featured" tinyint NOT NULL DEFAULT 0,
   "language" nvarchar(7) NOT NULL,
-  "xreference" nvarchar(50) NOT NULL,
+  "xreference" nvarchar(50) NOT NULL DEFAULT '',
  CONSTRAINT "PK_#__content_id" PRIMARY KEY CLUSTERED
 (
   "id" ASC
@@ -671,7 +671,7 @@ CREATE TABLE "#__extensions" (
   "manifest_cache" nvarchar(max) NOT NULL,
   "params" nvarchar(max) NOT NULL,
   "custom_data" nvarchar(max) NOT NULL,
-  "system_data" nvarchar(max) NOT NULL DEFAULT '',
+  "system_data" nvarchar(max) NOT NULL,
   "checked_out" bigint NOT NULL DEFAULT 0,
   "checked_out_time" datetime2(0) NOT NULL DEFAULT '1900-01-01 00:00:00',
   "ordering" int NULL DEFAULT 0,
@@ -880,7 +880,7 @@ SET IDENTITY_INSERT "#__extensions" OFF;
 
 CREATE TABLE "#__fields" (
   "id" int IDENTITY(1,1) NOT NULL,
-  "asset_id" int NOT NULL DEFAULT 0,
+  "asset_id" bigint NOT NULL DEFAULT 0,
   "context" nvarchar(255) NOT NULL DEFAULT '',
   "group_id" int NOT NULL DEFAULT 0,
   "title" nvarchar(255) NOT NULL DEFAULT '',
@@ -949,7 +949,7 @@ WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW
 
 CREATE TABLE "#__fields_groups" (
   "id" int IDENTITY(1,1) NOT NULL,
-  "asset_id" int NOT NULL DEFAULT 0,
+  "asset_id" bigint NOT NULL DEFAULT 0,
   "context" nvarchar(255) NOT NULL DEFAULT '',
   "title" nvarchar(255) NOT NULL DEFAULT '',
   "note" nvarchar(255) NOT NULL DEFAULT '',
@@ -1890,20 +1890,14 @@ CREATE TABLE "#__languages" (
   "published" int NOT NULL DEFAULT 0,
   "access" bigint NOT NULL DEFAULT 0,
   "ordering" int NOT NULL DEFAULT 0,
- CONSTRAINT "PK_#__languages_lang_id" PRIMARY KEY CLUSTERED
-(
-  "lang_id" ASC
-)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
- CONSTRAINT "#__languages$idx_sef" UNIQUE NONCLUSTERED
-(
-  "sef" ASC
-)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
-) ON [PRIMARY];
+  CONSTRAINT "PK_#__languages_lang_id" PRIMARY KEY ("lang_id") ON [PRIMARY],
+  CONSTRAINT "#__languages$idx_sef" UNIQUE ("sef") ON [PRIMARY],
+  CONSTRAINT "#__languages$idx_langcode" UNIQUE ("lang_code") ON [PRIMARY]
+)
+ON [PRIMARY];
 
-CREATE UNIQUE INDEX "idx_access" ON "#__languages"
-(
-  "access" ASC
-)WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF);
+CREATE INDEX "idx_ordering" ON "#__languages" ("ordering");
+CREATE INDEX "idx_access" ON "#__languages" ("access");
 
 --
 -- Dumping data for table `#__languages`
@@ -2247,7 +2241,7 @@ CREATE TABLE "#__newsfeeds" (
   "metakey" nvarchar(max) NOT NULL,
   "metadesc" nvarchar(max) NOT NULL,
   "metadata" nvarchar(max) NOT NULL,
-  "xreference" nvarchar(50) NOT NULL,
+  "xreference" nvarchar(50) NOT NULL DEFAULT '',
   "publish_up" datetime2(0) NOT NULL DEFAULT '1900-01-01 00:00:00',
   "publish_down" datetime2(0) NOT NULL DEFAULT '1900-01-01 00:00:00',
   "description" nvarchar(max) NOT NULL,
@@ -2735,7 +2729,7 @@ CREATE TABLE "#__updates" (
   "folder" nvarchar(20) DEFAULT '',
   "client_id" smallint DEFAULT 0,
   "version" nvarchar(32) DEFAULT '',
-  "data" nvarchar(max) NOT NULL DEFAULT '',
+  "data" nvarchar(max) NOT NULL,
   "detailsurl" nvarchar(max) NOT NULL,
   "infourl" nvarchar(max) NOT NULL,
   "extra_query" nvarchar(1000) NULL DEFAULT '',
diff --git a/libraries/cms/installer/adapter/language.php b/libraries/cms/installer/adapter/language.php
index 3138e941dd541..1569640cc054f 100644
--- a/libraries/cms/installer/adapter/language.php
+++ b/libraries/cms/installer/adapter/language.php
@@ -292,7 +292,7 @@ protected function _install($cname, $basePath, $clientId, &$element)
 		$row->set('params', $this->parent->getParams());
 		$row->set('manifest_cache', $this->parent->generateManifestCache());
 
-		if (!$row->store())
+		if (!$row->check() || !$row->store())
 		{
 			// Install failed, roll back changes
 			$this->parent->abort(JText::sprintf('JLIB_INSTALLER_ABORT', $row->getError()));
@@ -537,7 +537,7 @@ public function update()
 
 		// Update an entry to the extension table
 		$row = JTable::getInstance('extension');
-		$eid = $row->find(array('element' => strtolower($this->get('tag')), 'type' => 'language', 'client_id' => $clientId));
+		$eid = $row->find(array('element' => $this->get('tag'), 'type' => 'language', 'client_id' => $clientId));
 
 		if ($eid)
 		{
@@ -564,7 +564,7 @@ public function update()
 		// Clean installed languages cache.
 		JFactory::getCache()->clean('com_languages');
 
-		if (!$row->store())
+		if (!$row->check() || !$row->store())
 		{
 			// Install failed, roll back changes
 			$this->parent->abort(JText::sprintf('JLIB_INSTALLER_ABORT', $row->getError()));
@@ -794,6 +794,7 @@ public function discover_install()
 		// @todo remove code: $this->parent->extension->params = $this->parent->getParams();
 		try
 		{
+			$this->parent->extension->check();
 			$this->parent->extension->store();
 		}
 		catch (RuntimeException $e)
diff --git a/libraries/joomla/table/extension.php b/libraries/joomla/table/extension.php
index b6ec83341a794..6599c5f8c42c3 100644
--- a/libraries/joomla/table/extension.php
+++ b/libraries/joomla/table/extension.php
@@ -49,6 +49,19 @@ public function check()
 			return false;
 		}
 
+		if (!$this->extension_id)
+		{
+			if (!$this->custom_data)
+			{
+				$this->custom_data = '';
+			}
+
+			if (!$this->system_data)
+			{
+				$this->system_data = '';
+			}
+		}
+
 		return true;
 	}
 
diff --git a/libraries/joomla/table/update.php b/libraries/joomla/table/update.php
index 1d23878be1d23..9ac2ffa22f987 100644
--- a/libraries/joomla/table/update.php
+++ b/libraries/joomla/table/update.php
@@ -49,6 +49,11 @@ public function check()
 			return false;
 		}
 
+		if (!$this->update_id && !$this->data)
+		{
+			$this->data = '';
+		}
+
 		return true;
 	}
 
diff --git a/libraries/joomla/updater/updater.php b/libraries/joomla/updater/updater.php
index b75b9ffd183ea..63d451c4ff7c3 100644
--- a/libraries/joomla/updater/updater.php
+++ b/libraries/joomla/updater/updater.php
@@ -157,6 +157,7 @@ public function findUpdates($eid = 0, $cacheTimeout = 0, $minimum_stability = se
 				/** @var JTableUpdate $update */
 				foreach ($updateObjects as $update)
 				{
+					$update->check();
 					$update->store();
 				}
 			}