diff --git a/wwwroot/inc/install.php b/wwwroot/inc/install.php
index c72af7a36..333ce9b8f 100644
--- a/wwwroot/inc/install.php
+++ b/wwwroot/inc/install.php
@@ -1171,10 +1171,10 @@ function get_pseudo_file ($name)
   `mutex_rev` int(10) unsigned NOT NULL default '0',
   `out_of_sync` enum('yes','no') NOT NULL default 'yes',
   `last_errno` int(10) unsigned NOT NULL default '0',
-  `last_change` timestamp NOT NULL default '0000-00-00 00:00:00',
-  `last_push_started` timestamp NOT NULL default '0000-00-00 00:00:00',
-  `last_push_finished` timestamp NOT NULL default '0000-00-00 00:00:00',
-  `last_error_ts` timestamp NOT NULL default '0000-00-00 00:00:00',
+  `last_change` timestamp NULL default NULL,
+  `last_push_started` timestamp NULL default NULL,
+  `last_push_finished` timestamp NULL default NULL,
+  `last_error_ts` timestamp NULL default NULL,
   UNIQUE KEY `object_id` (`object_id`),
   KEY `domain_id` (`domain_id`),
   KEY `template_id` (`template_id`),
diff --git a/wwwroot/inc/pre-init.php b/wwwroot/inc/pre-init.php
index df1eac4a3..281aa8cad 100644
--- a/wwwroot/inc/pre-init.php
+++ b/wwwroot/inc/pre-init.php
@@ -58,11 +58,7 @@ function connectDB()
 	$drvoptions = array
 	(
 		PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
-		// Cancel one specific SQL mode option that RackTables has been non-compliant
-		// with but which used to be off by default until MySQL 5.7. As soon as
-		// respective SQL queries and table columns become compliant with those options
-		// stop changing @@SQL_MODE but still keep SET NAMES in place.
-		PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES "utf8", @@SQL_MODE = REPLACE(@@SQL_MODE, "NO_ZERO_DATE", "")',
+		PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES "utf8"',
 	);
 	if (isset ($pdo_bufsize))
 		$drvoptions[PDO::MYSQL_ATTR_MAX_BUFFER_SIZE] = $pdo_bufsize;
diff --git a/wwwroot/inc/upgrade.php b/wwwroot/inc/upgrade.php
index eaf2458f9..1d57ed6f4 100644
--- a/wwwroot/inc/upgrade.php
+++ b/wwwroot/inc/upgrade.php
@@ -1948,6 +1948,18 @@ function getUpgradeBatch ($batchid)
 			$query[] = "ALTER TABLE LDAPCache MODIFY COLUMN last_retry timestamp NULL DEFAULT NULL";
 			$query[] = "DELETE FROM LDAPCache";
 
+			$query[] = "ALTER TABLE VLANSwitch MODIFY COLUMN last_change timestamp NULL DEFAULT NULL";
+			$query[] = "UPDATE VLANSwitch set last_change = NULL WHERE last_change = '0000-00-00 00:00:00";
+
+			$query[] = "ALTER TABLE VLANSwitch MODIFY COLUMN last_push timestamp NULL DEFAULT NULL";
+			$query[] = "UPDATE VLANSwitch set last_push = NULL WHERE last_push = '0000-00-00 00:00:00";
+
+			$query[] = "ALTER TABLE VLANSwitch MODIFY COLUMN last_push_finished timestamp NULL DEFAULT NULL";
+			$query[] = "UPDATE VLANSwitch set last_push_finish = NULL WHERE last_push_finish = '0000-00-00 00:00:00";
+
+			$query[] = "ALTER TABLE VLANSwitch MODIFY COLUMN last_error_ts timestamp NULL DEFAULT NULL";
+			$query[] = "UPDATE VLANSwitch set last_error_ts = NULL WHERE last_error_ts = '0000-00-00 00:00:00";
+
 			$query[] = "INSERT INTO ObjectParentCompat (parent_objtype_id, child_objtype_id) VALUES (1787,4)";
 
 			$port_trigger_body = <<<ENDOFTRIGGER