diff --git a/admin_domains.php b/admin_domains.php
index f731d59c..c2804a16 100644
--- a/admin_domains.php
+++ b/admin_domains.php
@@ -528,7 +528,7 @@ if ($page == 'domains' || $page == 'overview') {
 
 				$ipandports = array();
 				if (isset($_POST['ipandport']) && ! is_array($_POST['ipandport'])) {
-					$_POST['ipandport'] = unserialize($_POST['ipandport']);
+					$_POST['ipandport'] = json_decode($_POST['ipandport'], true);
 				}
 
 				if (isset($_POST['ipandport']) && is_array($_POST['ipandport'])) {
@@ -564,7 +564,7 @@ if ($page == 'domains' || $page == 'overview') {
 
 					$ssl_ipandports = array();
 					if (isset($_POST['ssl_ipandport']) && ! is_array($_POST['ssl_ipandport'])) {
-						$_POST['ssl_ipandport'] = unserialize($_POST['ssl_ipandport']);
+						$_POST['ssl_ipandport'] = json_decode($_POST['ssl_ipandport'], true);
 					}
 
 					// Verify SSL-Ports
@@ -606,7 +606,7 @@ if ($page == 'domains' || $page == 'overview') {
 						$ssl_redirect = 0;
 						$letsencrypt = 0;
 						$http2 = 0;
-						// we need this for the serialize
+						// we need this for the json-encode
 						// if ssl is disabled or no ssl-ip/port exists
 						$ssl_ipandports[] = - 1;
 
@@ -622,7 +622,7 @@ if ($page == 'domains' || $page == 'overview') {
 					$ssl_redirect = 0;
 					$letsencrypt = 0;
 					$http2 = 0;
-					// we need this for the serialize
+					// we need this for the json-encode
 					// if ssl is disabled or no ssl-ip/port exists
 					$ssl_ipandports[] = - 1;
 
@@ -692,7 +692,7 @@ if ($page == 'domains' || $page == 'overview') {
 					}
 
 					if (count($ssl_ipandports) == 0) {
-						// we need this for the serialize
+						// we need this for the json-encode
 						// if ssl is disabled or no ssl-ip/port exists
 						$ssl_ipandports[] = - 1;
 					}
@@ -794,9 +794,9 @@ if ($page == 'domains' || $page == 'overview') {
 						'dkim' => $dkim,
 						'speciallogfile' => $speciallogfile,
 						'selectserveralias' => $serveraliasoption,
-						'ipandport' => serialize($ipandports),
+						'ipandport' => json_encode($ipandports),
 						'ssl_redirect' => $ssl_redirect,
-						'ssl_ipandport' => serialize($ssl_ipandports),
+						'ssl_ipandport' => json_encode($ssl_ipandports),
 						'phpenabled' => $phpenabled,
 						'openbasedir' => $openbasedir,
 						'phpsettingid' => $phpsettingid,
@@ -1420,7 +1420,7 @@ if ($page == 'domains' || $page == 'overview') {
 
 				$ipandports = array();
 				if (isset($_POST['ipandport']) && ! is_array($_POST['ipandport'])) {
-					$_POST['ipandport'] = unserialize($_POST['ipandport']);
+					$_POST['ipandport'] = json_decode($_POST['ipandport'], true);
 				}
 				if (isset($_POST['ipandport']) && is_array($_POST['ipandport'])) {
 
@@ -1466,7 +1466,7 @@ if ($page == 'domains' || $page == 'overview') {
 
 					$ssl_ipandports = array();
 					if (isset($_POST['ssl_ipandport']) && ! is_array($_POST['ssl_ipandport'])) {
-						$_POST['ssl_ipandport'] = unserialize($_POST['ssl_ipandport']);
+						$_POST['ssl_ipandport'] = json_decode($_POST['ssl_ipandport'], true);
 					}
 					if (isset($_POST['ssl_ipandport']) && is_array($_POST['ssl_ipandport'])) {
 
@@ -1494,7 +1494,7 @@ if ($page == 'domains' || $page == 'overview') {
 						$ssl_redirect = 0;
 						$letsencrypt = 0;
 						$http2 = 0;
-						// we need this for the serialize
+						// we need this for the json-encode
 						// if ssl is disabled or no ssl-ip/port exists
 						$ssl_ipandports[] = - 1;
 
@@ -1510,7 +1510,7 @@ if ($page == 'domains' || $page == 'overview') {
 					$ssl_redirect = 0;
 					$letsencrypt = 0;
 					$http2 = 0;
-					// we need this for the serialize
+					// we need this for the json-encode
 					// if ssl is disabled or no ssl-ip/port exists
 					$ssl_ipandports[] = - 1;
 
@@ -1603,7 +1603,7 @@ if ($page == 'domains' || $page == 'overview') {
 					}
 
 					if (count($ssl_ipandports) == 0) {
-						// we need this for the serialize
+						// we need this for the json-encode
 						// if ssl is disabled or no ssl-ip/port exists
 						$ssl_ipandports[] = - 1;
 					}
@@ -1668,8 +1668,8 @@ if ($page == 'domains' || $page == 'overview') {
 					'issubof' => $issubof,
 					'speciallogfile' => $speciallogfile,
 					'speciallogverified' => $speciallogverified,
-					'ipandport' => serialize($ipandports),
-					'ssl_ipandport' => serialize($ssl_ipandports),
+					'ipandport' => json_encode($ipandports),
+					'ssl_ipandport' => json_encode($ssl_ipandports),
 					'letsencrypt' => $letsencrypt,
 					'http2' => $http2,
 					'hsts_maxage' => $hsts_maxage,
diff --git a/customer_extras.php b/customer_extras.php
index 5800805d..5ef3cb61 100644
--- a/customer_extras.php
+++ b/customer_extras.php
@@ -563,7 +563,7 @@ if ($page == 'overview') {
 			$existing_backupJob = null;
 			while ($entry = $sel_stmt->fetch())
 			{
-				$data = unserialize($entry['data']);
+				$data = json_decode($entry['data'], true);
 				if ($data['customerid'] == $userinfo['customerid']) {
 					$existing_backupJob = $entry;
 					break;
@@ -613,7 +613,7 @@ if ($page == 'overview') {
 
 				if (!empty($existing_backupJob)) {
 					$action = "abort";
-					$row = unserialize($entry['data']);
+					$row = json_decode($entry['data'], true);
 					$row['path'] = makeCorrectDir(str_replace($userinfo['documentroot'], "/", $row['destdir']));
 					$row['backup_web'] = ($row['backup_web'] == '1') ? $lng['panel']['yes'] : $lng['panel']['no'];
 					$row['backup_mail'] = ($row['backup_mail'] == '1') ? $lng['panel']['yes'] : $lng['panel']['no'];
diff --git a/dns_editor.php b/dns_editor.php
index 98a4d683..75b5978e 100644
--- a/dns_editor.php
+++ b/dns_editor.php
@@ -208,7 +208,7 @@ if ($action == 'add_record' && ! empty($_POST)) {
 
 	// check for duplicate
 	foreach ($dom_entries as $existing_entry) {
-		// compare serialized string of array
+		// compare json-encoded string of array
 		$check_entry = $existing_entry;
 		// new entry has no ID yet
 		unset($check_entry['id']);
@@ -218,9 +218,9 @@ if ($action == 'add_record' && ! empty($_POST)) {
 		$check_entry['prio'] = (int) $check_entry['prio'];
 		$check_entry['ttl'] = (int) $check_entry['ttl'];
 		$check_entry['domain_id'] = (int) $check_entry['domain_id'];
-		// serialize both
-		$check_entry = serialize($check_entry);
-		$new = serialize($new_entry);
+		// encode both
+		$check_entry = json_encode($check_entry);
+		$new = json_encode($new_entry);
 		// compare
 		if ($check_entry === $new) {
 			$errors[] = $lng['error']['dns_duplicate_entry'];
diff --git a/install/froxlor.sql b/install/froxlor.sql
index f39913fb..f445a0e9 100644
--- a/install/froxlor.sql
+++ b/install/froxlor.sql
@@ -692,7 +692,7 @@ opcache.interned_strings_buffer'),
 	('panel', 'password_special_char', '!?<>§$%+#=@'),
 	('panel', 'customer_hide_options', ''),
 	('panel', 'version', '0.9.39.5'),
-	('panel', 'db_version', '201805241');
+	('panel', 'db_version', '201805290');
 
 
 DROP TABLE IF EXISTS `panel_tasks`;
diff --git a/install/lib/class.FroxlorInstall.php b/install/lib/class.FroxlorInstall.php
index 1cbbd7ca..598bf66a 100644
--- a/install/lib/class.FroxlorInstall.php
+++ b/install/lib/class.FroxlorInstall.php
@@ -1015,6 +1015,16 @@ class FroxlorInstall
 			$content .= $this->_status_message('green', $this->_lng['requirements']['installed']);
 		}
 		
+		// check for json extension
+		$content .= $this->_status_message('begin', $this->_lng['requirements']['phpjson']);
+
+		if (! extension_loaded('json')) {
+			$content .= $this->_status_message('red', $this->_lng['requirements']['notinstalled']);
+			$_die = true;
+		} else {
+			$content .= $this->_status_message('green', $this->_lng['requirements']['installed']);
+		}
+
 		// check for bcmath extension
 		$content .= $this->_status_message('begin', $this->_lng['requirements']['phpbcmath']);
 		
@@ -1033,15 +1043,6 @@ class FroxlorInstall
 			$content .= $this->_status_message('green', $this->_lng['requirements']['installed']);
 		}
 
-		// check for json extension
-		$content .= $this->_status_message('begin', $this->_lng['requirements']['phpjson']);
-		
-		if (! extension_loaded('json')) {
-			$content .= $this->_status_message('orange', $this->_lng['requirements']['notinstalled'] . "<br />" . $this->_lng['requirements']['jsondescription']);
-		} else {
-			$content .= $this->_status_message('green', $this->_lng['requirements']['installed']);
-		}
-
 		// check for open_basedir
 		$content .= $this->_status_message('begin', $this->_lng['requirements']['openbasedir']);
 		$php_ob = @ini_get("open_basedir");
diff --git a/install/lng/english.lng.php b/install/lng/english.lng.php
index 8651bb83..a4cea2dc 100644
--- a/install/lng/english.lng.php
+++ b/install/lng/english.lng.php
@@ -38,7 +38,6 @@ $lng['requirements']['phpzip'] = 'PHP zip-extension...';
 $lng['requirements']['phpjson'] = 'PHP json-extension...';
 $lng['requirements']['bcmathdescription'] = 'Traffic-calculation related functions will not work correctly!';
 $lng['requirements']['zipdescription'] = 'The auto-update feature requires the zip extension.';
-$lng['requirements']['jsondescription'] = 'The settings import/export feature requires the json extension.';
 $lng['requirements']['openbasedir'] = 'open_basedir...';
 $lng['requirements']['openbasedirenabled'] = 'Froxlor will not work properly with open_basedir enabled. Please disable open_basedir for Froxlor in the coresponding php.ini';
 $lng['requirements']['diedbecauseofrequirements'] = 'Cannot install Froxlor without these requirements! Try to fix them and retry.';
diff --git a/install/lng/german.lng.php b/install/lng/german.lng.php
index d18e94c0..4e4638db 100644
--- a/install/lng/german.lng.php
+++ b/install/lng/german.lng.php
@@ -38,7 +38,6 @@ $lng['requirements']['phpzip'] = 'PHP zip-Erweiterung...';
 $lng['requirements']['phpjson'] = 'PHP json-Erweiterung...';
 $lng['requirements']['bcmathdescription'] = 'Traffic-Berechnungs bezogene Funktionen stehen nicht vollständig zur Verfügung!';
 $lng['requirements']['zipdescription'] = 'Die Auto-Update Funktion benötigt die zip Erweiterung.';
-$lng['requirements']['jsondescription'] = 'Die Einstellungen Import/Export Funktion benötigt die json Erweiterung.';
 $lng['requirements']['openbasedir'] = 'open_basedir genutzt wird...';
 $lng['requirements']['openbasedirenabled'] = 'Froxlor wird mit aktiviertem open_basedir nicht vollständig funktionieren. Bitte deaktivieren Sie open_basedir für Froxlor in der entsprechenden php.ini';
 $lng['requirements']['diedbecauseofrequirements'] = 'Kann Froxlor ohne diese Voraussetzungen nicht installieren! Beheben Sie die angezeigten Probleme und versuchen Sie es erneut.';
diff --git a/install/updates/froxlor/0.9/update_0.9.inc.php b/install/updates/froxlor/0.9/update_0.9.inc.php
index e5e3c60e..17432b94 100644
--- a/install/updates/froxlor/0.9/update_0.9.inc.php
+++ b/install/updates/froxlor/0.9/update_0.9.inc.php
@@ -3968,3 +3968,33 @@ if (isDatabaseVersion('201805240')) {
 
 	updateToDbVersion('201805241');
 }
+
+if (isDatabaseVersion('201805241')) {
+
+	$do_update = true;
+	showUpdateStep("Checking for required PHP json-extension");
+	if (! extension_loaded('json')) {
+		$do_update = false;
+		lastStepStatus(2, 'not installed');
+	} else {
+		lastStepStatus(0);
+
+		showUpdateStep("Checking for current cronjobs that need converting");
+		$result_tasks_stmt = Database::query("
+			SELECT * FROM `" . TABLE_PANEL_TASKS . "` ORDER BY `id` ASC
+		");
+		$upd_stmt = Database::prepare("UPDATE `" . TABLE_PANEL_TASKS . "` SET `data` = :data WHERE `id` = :taskid");
+		while ($row = $result_tasks_stmt->fetch(PDO::FETCH_ASSOC)) {
+			if (! empty($row['data'])) {
+				$data = unserialize($row['data']);
+				Database::pexecute($upd_stmt, array(
+					'data' => json_encode($data),
+					'taskid' => $row['id']
+				));
+			}
+		}
+		lastStepStatus(0);
+
+		updateToDbVersion('201805290');
+	}
+}
diff --git a/lib/classes/output/class.paging.php b/lib/classes/output/class.paging.php
index 8ee2bc25..64643b7d 100644
--- a/lib/classes/output/class.paging.php
+++ b/lib/classes/output/class.paging.php
@@ -114,7 +114,7 @@ class paging {
 		$this->userinfo = $userinfo;
 
 		if (!is_array($this->userinfo['lastpaging'])) {
-			$this->userinfo['lastpaging'] = unserialize($this->userinfo['lastpaging']);
+			$this->userinfo['lastpaging'] = json_decode($this->userinfo['lastpaging'], true);
 		}
 
 		$this->table = $table;
@@ -224,7 +224,7 @@ class paging {
 			AND `adminsession` = :adminsession
 		");
 		$upd_data = array(
-			'lastpaging' => serialize($this->userinfo['lastpaging']),
+			'lastpaging' => json_encode($this->userinfo['lastpaging']),
 			'hash' => $userinfo['hash'],
 			'userid' => $userinfo['userid'],
 			'ipaddr' => $userinfo['ipaddress'],
diff --git a/lib/functions/froxlor/function.CronjobFunctions.php b/lib/functions/froxlor/function.CronjobFunctions.php
index a2c09785..0b5f80ff 100644
--- a/lib/functions/froxlor/function.CronjobFunctions.php
+++ b/lib/functions/froxlor/function.CronjobFunctions.php
@@ -63,7 +63,7 @@ function getOutstandingTasks() {
 	while ($row = $result->fetch(PDO::FETCH_ASSOC)) {
 
 		if ($row['data'] != '') {
-			$row['data'] = unserialize($row['data']);
+			$row['data'] = json_decode($row['data'], true);
 		}
 
 		// rebuilding webserver-configuration
diff --git a/lib/functions/froxlor/function.inserttask.php b/lib/functions/froxlor/function.inserttask.php
index 3f2cdbde..705bf77e 100644
--- a/lib/functions/froxlor/function.inserttask.php
+++ b/lib/functions/froxlor/function.inserttask.php
@@ -70,7 +70,7 @@ function inserttask($type, $param1 = '', $param2 = '', $param3 = '', $param4 = '
 		$data['uid'] = $param2;
 		$data['gid'] = $param3;
 		$data['store_defaultindex'] = $param4;
-		$data = serialize($data);
+		$data = json_encode($data);
 		Database::pexecute($ins_stmt, array('type' => '2', 'data' => $data));
 
 	} elseif ($type == '6'
@@ -78,7 +78,7 @@ function inserttask($type, $param1 = '', $param2 = '', $param3 = '', $param4 = '
 	) {
 		$data = array();
 		$data['loginname'] = $param1;
-		$data = serialize($data);
+		$data = json_encode($data);
 		Database::pexecute($ins_stmt, array('type' => '6', 'data' => $data));
 
 	} elseif ($type == '7'
@@ -88,7 +88,7 @@ function inserttask($type, $param1 = '', $param2 = '', $param3 = '', $param4 = '
 		$data = array();
 		$data['loginname'] = $param1;
 		$data['email'] = $param2;
-		$data = serialize($data);
+		$data = json_encode($data);
 		Database::pexecute($ins_stmt, array('type' => '7', 'data' => $data));
 
 	} elseif ($type == '8'
@@ -98,13 +98,13 @@ function inserttask($type, $param1 = '', $param2 = '', $param3 = '', $param4 = '
 		$data = array();
 		$data['loginname'] = $param1;
 		$data['homedir'] = $param2;
-		$data = serialize($data);
+		$data = json_encode($data);
 		Database::pexecute($ins_stmt, array('type' => '8', 'data' => $data));
 
 	} elseif ($type == '20'
 		&& is_array($param1)
 	) {
-		$data = serialize($param1);
+		$data = json_encode($param1);
 		Database::pexecute($ins_stmt, array('type' => '20', 'data' => $data));
 	}
 }
diff --git a/scripts/jobs/cron_backup.php b/scripts/jobs/cron_backup.php
index b01fe1ed..131a2004 100644
--- a/scripts/jobs/cron_backup.php
+++ b/scripts/jobs/cron_backup.php
@@ -79,7 +79,7 @@ $all_jobs = $result_tasks_stmt->fetchAll();
 foreach ($all_jobs as $row) {
 
 	if ($row['data'] != '') {
-		$row['data'] = unserialize($row['data']);
+		$row['data'] = json_decode($row['data'], true);
 	}
 
 	if (is_array($row['data'])) {
diff --git a/scripts/jobs/cron_tasks.php b/scripts/jobs/cron_tasks.php
index b7176a53..48cbbb66 100644
--- a/scripts/jobs/cron_tasks.php
+++ b/scripts/jobs/cron_tasks.php
@@ -43,7 +43,7 @@ while ($row = $result_tasks_stmt->fetch(PDO::FETCH_ASSOC)) {
 	$resultIDs[] = $row['id'];
 
 	if ($row['data'] != '') {
-		$row['data'] = unserialize($row['data']);
+		$row['data'] = json_decode($row['data'], true);
 	}
 
 	/**