diff --git a/migrations/v210.php b/migrations/v210.php
index a9652c71..f357afc6 100644
--- a/migrations/v210.php
+++ b/migrations/v210.php
@@ -21,6 +21,7 @@ class v210 extends \phpbb\db\migration\migration
 		return array(
 			array('config.update', array('board3_portal_version', '2.1.0')),
 			array('custom', array(array($this, 'add_donation_setting'))),
+			array('custom', array(array($this, 'convert_serialize_to_json'))),
 		);
 	}
 
@@ -39,4 +40,66 @@ class v210 extends \phpbb\db\migration\migration
 		}
 		$this->db->sql_freeresult($result);
 	}
+
+	public function convert_serialize_to_json()
+	{
+		if (!function_exists('obtain_portal_config'))
+		{
+			include ($this->phpbb_root_path . 'ext/board3/portal/includes/functions.' . $this->php_ext);
+			define('PORTAL_CONFIG_TABLE', $this->table_prefix . 'portal_config');
+		}
+
+		$portal_config = obtain_portal_config();
+
+		$sql = 'SELECT module_id, module_classname
+			FROM ' . $this->table_prefix . 'portal_modules
+			WHERE ' . $this->db->sql_in_set('module_classname', array(
+				'\board3\portal\modules\calendar',
+				'\board3\portal\modules\links',
+				'\board3\portal\modules\main_menu',
+			));
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			switch ($row['module_classname'])
+			{
+				case '\board3\portal\modules\calendar':
+					$setting = 'board3_calendar_events_' . $row['module_id'];
+				break;
+				case '\board3\portal\modules\links':
+					$setting = 'board3_links_array_' . $row['module_id'];
+				break;
+				case '\board3\portal\modules\main_menu':
+					$setting = 'board3_menu_array_' . $row['module_id'];
+				break;
+				default:
+					// nothing
+			}
+
+			// Do not try to unserialize empty data
+			if (empty($setting) || empty($portal_config[$setting]))
+			{
+				continue;
+			}
+
+			// Save json encoded setting
+			set_portal_config($setting, json_encode($this->utf_unserialize($portal_config[$setting])));
+		}
+		$this->db->sql_freeresult($result);
+	}
+
+	/**
+	 * Unserialize links array
+	 *
+	 * @param string $serial_str Serialized string
+	 *
+	 * @return array Unserialized string
+	 */
+	private function utf_unserialize($serial_str)
+	{
+		$out = preg_replace_callback('!s:(\d+):"(.*?)";!s', function ($result) {
+			return 's:' . strlen($result[2]) . ":\"{$result[2]}\";";
+		}, $serial_str);
+		return unserialize($out);
+	}
 }
diff --git a/modules/calendar.php b/modules/calendar.php
index e4082674..074fc580 100644
--- a/modules/calendar.php
+++ b/modules/calendar.php
@@ -265,7 +265,7 @@ class calendar extends module_base
 		* Let's start displaying the events
 		* make sure we only display events in the future
 		*/
-		$events = $this->utf_unserialize($portal_config['board3_calendar_events_' . $module_id]);
+		$events = json_decode($portal_config['board3_calendar_events_' . $module_id], true);
 
 		if (!empty($events) && $this->config['board3_display_events_' . $module_id])
 		{
@@ -423,7 +423,7 @@ class calendar extends module_base
 		$link_id = $this->request->variable('id', 99999999); // 0 will trigger unwanted behavior, therefore we set a number we should never reach
 		$portal_config = obtain_portal_config();
 
-		$events = (strlen($portal_config['board3_calendar_events_' . $module_id]) >= 1) ? $this->utf_unserialize($portal_config['board3_calendar_events_' . $module_id]) : array();
+		$events = (strlen($portal_config['board3_calendar_events_' . $module_id]) >= 1) ? json_decode($portal_config['board3_calendar_events_' . $module_id], true) : array();
 
 		// append_sid() adds adm/ already, no need to add it here
 		$u_action = append_sid('index.' . $this->php_ext, 'i=\board3\portal\acp\portal_module&mode=config&module_id=' . $module_id);
@@ -533,7 +533,7 @@ class calendar extends module_base
 					$time_ary[$key] = $cur_event['start_time'];
 				}
 				array_multisort($time_ary, SORT_NUMERIC, $events);
-				$board3_events_array = serialize($events);
+				$board3_events_array = json_encode($events);
 				set_portal_config('board3_calendar_events_' . $module_id, $board3_events_array);
 
 				trigger_error($message . adm_back_link($u_action));
@@ -555,7 +555,7 @@ class calendar extends module_base
 					array_splice($events, $link_id, 1);
 					$events = array_merge($events);
 
-					$board3_events_array = serialize($events);
+					$board3_events_array = json_encode($events);
 					set_portal_config('board3_calendar_events_' . $module_id, $board3_events_array);
 
 					$this->log->add('admin', $this->user->data['user_id'], $this->user->data['user_ip'], 'LOG_PORTAL_EVENT_REMOVED', false, array($cur_event_title));
@@ -711,21 +711,6 @@ class calendar extends module_base
 		}
 	}
 
-	/**
-	 * Unserialize links array
-	 *
-	 * @param string $serial_str Serialized string
-	 *
-	 * @return array Unserialized string
-	 */
-	private function utf_unserialize($serial_str)
-	{
-		$out = preg_replace_callback('!s:(\d+):"(.*?)";!s', function ($result) {
-			return 's:' . strlen($result[2]) . ":\"{$result[2]}\";";
-		}, $serial_str);
-		return unserialize($out);
-	}
-
 	/**
 	* Validate URLs and execute apppend_sid if necessary
 	*
diff --git a/modules/links.php b/modules/links.php
index 2db14e1c..539c4374 100644
--- a/modules/links.php
+++ b/modules/links.php
@@ -111,7 +111,7 @@ class links extends module_base
 	{
 		$portal_config = obtain_portal_config();
 
-		$links = $this->utf_unserialize($portal_config['board3_links_array_' . $module_id]);
+		$links = json_decode($portal_config['board3_links_array_' . $module_id], true);
 
 		// get user's groups
 		$groups_ary = get_user_groups();
@@ -200,7 +200,7 @@ class links extends module_base
 			);
 		}
 
-		$board3_menu_array = serialize($links);
+		$board3_menu_array = json_encode($links);
 		set_portal_config('board3_links_array_' . $module_id, $board3_menu_array);
 		$this->config->set('board3_links_' . $module_id, '');
 		$this->config->set('board3_links_url_new_window_' . $module_id, 0);
@@ -247,7 +247,7 @@ class links extends module_base
 		$link_id = $this->request->variable('id', 99999999); // 0 will trigger unwanted behavior, therefore we set a number we should never reach
 		$portal_config = obtain_portal_config();
 
-		$links = $this->utf_unserialize($portal_config['board3_links_array_' . $module_id]);
+		$links = json_decode($portal_config['board3_links_array_' . $module_id], true);
 
 		$u_action = append_sid('index.' . $this->php_ext, 'i=\board3\portal\acp\portal_module&mode=config&module_id=' . $module_id);
 
@@ -319,7 +319,7 @@ class links extends module_base
 					$this->log->add('admin', $this->user->data['user_id'], $this->user->data['user_ip'],'LOG_PORTAL_LINK_ADDED', false, array($link_title));
 				}
 
-				$board3_links_array = serialize($links);
+				$board3_links_array = json_encode($links);
 				set_portal_config('board3_links_array_' . $module_id, $board3_links_array);
 
 				trigger_error($message . adm_back_link($u_action));
@@ -341,7 +341,7 @@ class links extends module_base
 					array_splice($links, $link_id, 1);
 					$links = array_merge($links);
 
-					$board3_links_array = serialize($links);
+					$board3_links_array = json_encode($links);
 					set_portal_config('board3_links_array_' . $module_id, $board3_links_array);
 
 					$this->log->add('admin', $this->user->data['user_id'], $this->user->data['user_ip'], 'LOG_PORTAL_LINK_REMOVED', false, array($cur_link_title));
@@ -397,7 +397,7 @@ class links extends module_base
 				// insert the info of the moved link
 				$links[$switch_order_id] = $cur_link;
 
-				$board3_links_array = serialize($links);
+				$board3_links_array = json_encode($links);
 				set_portal_config('board3_links_array_' . $module_id, $board3_links_array);
 
 			break;
@@ -460,19 +460,4 @@ class links extends module_base
 	{
 		$this->manage_links('', $key, $module_id);
 	}
-
-	/**
-	 * Unserialize links array
-	 *
-	 * @param string $serial_str Serialized string
-	 *
-	 * @return array Unserialized string
-	 */
-	private function utf_unserialize($serial_str)
-	{
-		$out = preg_replace_callback('!s:(\d+):"(.*?)";!s', function ($result) {
-			return 's:' . strlen($result[2]) . ":\"{$result[2]}\";";
-		}, $serial_str);
-		return unserialize($out);
-	}
 }
diff --git a/modules/main_menu.php b/modules/main_menu.php
index a06cec95..c814bab2 100644
--- a/modules/main_menu.php
+++ b/modules/main_menu.php
@@ -112,7 +112,7 @@ class main_menu extends module_base
 	{
 		$portal_config = obtain_portal_config();
 
-		$links = $this->utf_unserialize($portal_config['board3_menu_array_' . $module_id]);
+		$links = json_decode($portal_config['board3_menu_array_' . $module_id], true);
 
 		$this->template->assign_block_vars('portal_menu', array('MODULE_ID' => $module_id));
 
@@ -255,7 +255,7 @@ class main_menu extends module_base
 			);
 		}
 
-		$board3_menu_array = serialize($links);
+		$board3_menu_array = json_encode($links);
 		set_portal_config('board3_menu_array_' . $module_id, $board3_menu_array);
 		$this->config->set('board3_menu_' . $module_id, '');
 		$this->config->set('board3_menu_url_new_window_' . $module_id, 0);
@@ -302,7 +302,7 @@ class main_menu extends module_base
 		$link_id = $this->request->variable('id', 99999999); // 0 will trigger unwanted behavior, therefore we set a number we should never reach
 		$portal_config = obtain_portal_config();
 
-		$links = $this->utf_unserialize($portal_config['board3_menu_array_' . $module_id]);
+		$links = json_decode($portal_config['board3_menu_array_' . $module_id], true);
 
 		$u_action = append_sid('index.' . $this->php_ext, 'i=%5Cboard3%5Cportal%5Cacp%5Cportal_module&mode=config&module_id=' . $module_id);
 
@@ -379,7 +379,7 @@ class main_menu extends module_base
 					$this->log->add('admin', $this->user->data['user_id'], $this->user->data['user_ip'], 'LOG_PORTAL_LINK_ADDED', false, array($link_title));
 				}
 
-				$board3_menu_array = serialize($links);
+				$board3_menu_array = json_encode($links);
 				set_portal_config('board3_menu_array_' . $module_id, $board3_menu_array);
 
 				trigger_error($message . adm_back_link($u_action));
@@ -401,7 +401,7 @@ class main_menu extends module_base
 					array_splice($links, $link_id, 1);
 					$links = array_merge($links);
 
-					$board3_menu_array = serialize($links);
+					$board3_menu_array = json_encode($links);
 					set_portal_config('board3_menu_array_' . $module_id, $board3_menu_array);
 
 					$this->log->add('admin', $this->user->data['user_id'], $this->user->data['user_ip'], 'LOG_PORTAL_LINK_REMOVED', false, array($cur_link_title));
@@ -457,7 +457,7 @@ class main_menu extends module_base
 				// insert the info of the moved link
 				$links[$switch_order_id] = $cur_link;
 
-				$board3_menu_array = serialize($links);
+				$board3_menu_array = json_encode($links);
 				set_portal_config('board3_menu_array_' . $module_id, $board3_menu_array);
 
 			break;
@@ -524,19 +524,4 @@ class main_menu extends module_base
 	{
 		$this->manage_links('', $key, $module_id);
 	}
-
-	/**
-	 * Unserialize links array
-	 *
-	 * @param string $serial_str Serialized string
-	 *
-	 * @return array Unserialized string
-	 */
-	private function utf_unserialize($serial_str)
-	{
-		$out = preg_replace_callback('!s:(\d+):"(.*?)";!s', function ($result) {
-			return 's:' . strlen($result[2]) . ":\"{$result[2]}\";";
-		}, $serial_str);
-		return unserialize($out);
-	}
 }