diff --git a/advancedcontentfilter/advancedcontentfilter.php b/advancedcontentfilter/advancedcontentfilter.php
index ce5da9c36..3f0364886 100644
--- a/advancedcontentfilter/advancedcontentfilter.php
+++ b/advancedcontentfilter/advancedcontentfilter.php
@@ -39,7 +39,6 @@ use Friendica\Content\Text\Markdown;
 use Friendica\Core\Addon;
 use Friendica\Core\Cache;
 use Friendica\Core\L10n;
-use Friendica\Core\System;
 use Friendica\Database\DBA;
 use Friendica\Database\DBStructure;
 use Friendica\Model\Item;
@@ -47,7 +46,6 @@ use Friendica\Model\Term;
 use Friendica\Module\Login;
 use Friendica\Network\HTTPException;
 use Friendica\Util\DateTimeFormat;
-use Friendica\Util\Security;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
 use Symfony\Component\ExpressionLanguage;
@@ -91,7 +89,7 @@ function advancedcontentfilter_dbstructure_definition(App $a, &$database)
 			"expression" => ["type" => "mediumtext"  , "not null" => "1", "comment" => "Expression text"],
 			"serialized" => ["type" => "mediumtext"  , "not null" => "1", "comment" => "Serialized parsed expression"],
 			"active"     => ["type" => "boolean"     , "not null" => "1", "default" => "1", "comment" => "Whether the rule is active or not"],
-			"created"    => ["type" => "datetime"    , "not null" => "1", "default" => NULL_DATE, "comment" => "Creation date"],
+			"created"    => ["type" => "datetime"    , "not null" => "1", "default" => DBA::NULL_DATETIME, "comment" => "Creation date"],
 		],
 		"indexes" => [
 			"PRIMARY" => ["id"],
diff --git a/public_server/public_server.php b/public_server/public_server.php
index 4d552951a..2b36f3f69 100644
--- a/public_server/public_server.php
+++ b/public_server/public_server.php
@@ -6,13 +6,13 @@
  * Author: Keith Fernie <http://friendika.me4.it/profile/keith>
  */
 
+use Friendica\App;
 use Friendica\BaseModule;
 use Friendica\Core\Addon;
 use Friendica\Core\Config;
 use Friendica\Core\L10n;
 use Friendica\Database\DBA;
 use Friendica\Util\DateTimeFormat;
-use Friendica\Util\Security;
 
 function public_server_install()
 {
@@ -32,7 +32,7 @@ function public_server_uninstall()
 	Addon::unregisterHook('logged_in', 'addon/public_server/public_server.php', 'public_server_login');
 }
 
-function public_server_load_config(\Friendica\App $a)
+function public_server_load_config(App $a)
 {
 	$a->loadConfigFile(__DIR__. '/config/public_server.ini.php');
 }
@@ -59,7 +59,7 @@ function public_server_cron($a, $b)
 	$r = q("SELECT * FROM `user` WHERE `account_expires_on` < UTC_TIMESTAMP() + INTERVAL 5 DAY AND
 		`account_expires_on` > '%s' AND
 		`expire_notification_sent` <= '%s'",
-		DBA::escape(NULL_DATE), DBA::escape(NULL_DATE));
+		DBA::NULL_DATETIME, DBA::NULL_DATETIME);
 
 	if (DBA::isResult($r)) {
 		foreach ($r as $rr) {
@@ -83,7 +83,7 @@ function public_server_cron($a, $b)
 	$nologin = Config::get('public_server', 'nologin', false);
 	if ($nologin) {
 		$r = q("SELECT `uid` FROM `user` WHERE NOT `account_expired` AND `login_date` <= '%s' AND `register_date` < UTC_TIMESTAMP() - INTERVAL %d DAY AND `account_expires_on` <= '%s'",
-			DBA::escape(NULL_DATE), intval($nologin), DBA::escape(NULL_DATE));
+			DBA::NULL_DATETIME, intval($nologin), DBA::NULL_DATETIME);
 		if (DBA::isResult($r)) {
 			foreach ($r as $rr) {
 				$fields = ['account_expires_on' => DateTimeFormat::utc('now +6 days')];
@@ -95,7 +95,7 @@ function public_server_cron($a, $b)
 	$flagusers = Config::get('public_server', 'flagusers', false);
 	if ($flagusers) {
 		$r = q("SELECT `uid` FROM `user` WHERE NOT `account_expired` AND `login_date` < UTC_TIMESTAMP() - INTERVAL %d DAY AND `account_expires_on` <= '%s' AND `page-flags` = 0",
-			intval($flagusers), DBA::escape(NULL_DATE));
+			intval($flagusers), DBA::NULL_DATETIME);
 		if (DBA::isResult($r)) {
 			foreach ($r as $rr) {
 				$fields = ['account_expires_on' => DateTimeFormat::utc('now +6 days')];
@@ -108,7 +108,7 @@ function public_server_cron($a, $b)
 	$flagpostsexpire = Config::get('public_server', 'flagpostsexpire');
 	if ($flagposts && $flagpostsexpire) {
 		$r = q("SELECT `uid` FROM `user` WHERE NOT `account_expired` AND `login_date` < UTC_TIMESTAMP() - INTERVAL %d DAY AND `account_expires_on` <= '%s' and `expire` = 0 AND `page-flags` = 0",
-			intval($flagposts), DBA::escape(NULL_DATE));
+			intval($flagposts), DBA::NULL_DATETIME);
 		if (DBA::isResult($r)) {
 			foreach ($r as $rr) {
 				DBA::update('user', ['expire' => $flagpostsexpire], ['uid' => $rr['uid']]);
@@ -138,7 +138,7 @@ function public_server_login($a, $b)
 	}
 
 	$fields = ['account_expires_on' => DateTimeFormat::utc('now +' . $days . ' days')];
-	$condition = ["`uid` = ? AND `account_expires_on` > ?", local_user(), NULL_DATE];
+	$condition = ["`uid` = ? AND `account_expires_on` > ?", local_user(), DBA::NULL_DATETIME];
 	DBA::update('user', $fields, $condition);
 }