diff --git a/Admin/Activate.php b/Admin/Activate.php
index a9fed10..f4ddc92 100644
--- a/Admin/Activate.php
+++ b/Admin/Activate.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -16,7 +16,7 @@
 namespace Modules\Calendar\Admin;
 
 
-use phpOMS\DataStorage\Database\Pool;
+use phpOMS\DataStorage\Database\DatabasePool;
 use phpOMS\Module\ActivateAbstract;
 use phpOMS\Module\InfoManager;
 
@@ -37,7 +37,7 @@ class Activate extends ActivateAbstract
     /**
      * {@inheritdoc}
      */
-    public static function activate(Pool $dbPool, InfoManager $info)
+    public static function activate(DatabasePool $dbPool, InfoManager $info)
     {
         parent::activate($dbPool, $info);
     }
diff --git a/Admin/Deactivate.php b/Admin/Deactivate.php
index eb36027..10dddd5 100644
--- a/Admin/Deactivate.php
+++ b/Admin/Deactivate.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -16,7 +16,7 @@
 namespace Modules\Calendar\Admin;
 
 
-use phpOMS\DataStorage\Database\Pool;
+use phpOMS\DataStorage\Database\DatabasePool;
 use phpOMS\Module\DeactivateAbstract;
 use phpOMS\Module\InfoManager;
 
@@ -37,7 +37,7 @@ class Deactivate extends DeactivateAbstract
     /**
      * {@inheritdoc}
      */
-    public static function deactivate(Pool $dbPool, InfoManager $info)
+    public static function deactivate(DatabasePool $dbPool, InfoManager $info)
     {
         parent::deactivate($dbPool, $info);
     }
diff --git a/Admin/Install/Navigation.php b/Admin/Install/Navigation.php
index 21b15a3..92a472a 100644
--- a/Admin/Install/Navigation.php
+++ b/Admin/Install/Navigation.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -14,7 +14,7 @@
  * @link       http://orange-management.com
  */
 namespace Modules\Calendar\Admin\Install;
-use phpOMS\DataStorage\Database\Pool;
+use phpOMS\DataStorage\Database\DatabasePool;
 
 /**
  * Navigation class.
@@ -29,7 +29,7 @@ use phpOMS\DataStorage\Database\Pool;
  */
 class Navigation
 {
-    public static function install(Pool $dbPool)
+    public static function install(string $path, DatabasePool $dbPool)
     {
         $navData = json_decode(file_get_contents(__DIR__ . '/Navigation.install.json'), true);
 
diff --git a/Admin/Installer.php b/Admin/Installer.php
index ff31264..28e8571 100644
--- a/Admin/Installer.php
+++ b/Admin/Installer.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -16,7 +16,7 @@
 namespace Modules\Calendar\Admin;
 
 use phpOMS\DataStorage\Database\DatabaseType;
-use phpOMS\DataStorage\Database\Pool;
+use phpOMS\DataStorage\Database\DatabasePool;
 use phpOMS\Module\InfoManager;
 use phpOMS\Module\InstallerAbstract;
 
@@ -37,9 +37,9 @@ class Installer extends InstallerAbstract
     /**
      * {@inheritdoc}
      */
-    public static function install(Pool $dbPool, InfoManager $info)
+    public static function install(string $path, DatabasePool $dbPool, InfoManager $info)
     {
-        parent::install($dbPool, $info);
+        parent::install($path, $dbPool, $info);
 
         switch ($dbPool->get('core')->getType()) {
             case DatabaseType::MYSQL:
@@ -75,7 +75,7 @@ class Installer extends InstallerAbstract
 
                 $dbPool->get('core')->con->prepare(
                     'ALTER TABLE `' . $dbPool->get('core')->prefix . 'calendar_permission`
-                            ADD CONSTRAINT `' . $dbPool->get('core')->prefix . 'calendar_permission_ibfk_2` FOREIGN KEY (`calendar_permission_calendar`) REFERENCES `' . $dbPool->get('core')->prefix . 'calendar` (`calendar_id`);'
+                            ADD CONSTRAINT `' . $dbPool->get('core')->prefix . 'calendar_permission_ibfk_1` FOREIGN KEY (`calendar_permission_calendar`) REFERENCES `' . $dbPool->get('core')->prefix . 'calendar` (`calendar_id`);'
                 )->execute();
 
                 $dbPool->get('core')->con->prepare(
@@ -93,10 +93,16 @@ class Installer extends InstallerAbstract
                             `schedule_end` datetime DEFAULT NULL,
                             `schedule_created_at` datetime NOT NULL,
                             `schedule_created_by` int(11) NOT NULL,
-                            PRIMARY KEY (`schedule_id`)
+                            PRIMARY KEY (`schedule_id`),
+                            KEY `schedule_created_by` (`schedule_created_by`)
                         )ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1;'
                 )->execute();
 
+                $dbPool->get('core')->con->prepare(
+                    'ALTER TABLE `' . $dbPool->get('core')->prefix . 'schedule`
+                            ADD CONSTRAINT `' . $dbPool->get('core')->prefix . 'schedule_ibfk_1` FOREIGN KEY (`schedule_created_by`) REFERENCES `' . $dbPool->get('core')->prefix . 'account` (`account_id`);'
+                )->execute();
+
                 $dbPool->get('core')->con->prepare(
                     'CREATE TABLE if NOT EXISTS `' . $dbPool->get('core')->prefix . 'calendar_event` (
                             `calendar_event_id` int(11) NOT NULL AUTO_INCREMENT,
diff --git a/Admin/Uninstall.php b/Admin/Uninstall.php
index 2f84f6b..7bacf36 100644
--- a/Admin/Uninstall.php
+++ b/Admin/Uninstall.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -16,7 +16,7 @@
 namespace Modules\Calendar\Admin;
 
 
-use phpOMS\DataStorage\Database\Pool;
+use phpOMS\DataStorage\Database\DatabasePool;
 use phpOMS\DataStorage\Database\Schema\Builder;
 use phpOMS\Module\UninstallAbstract;
 
@@ -37,7 +37,7 @@ class Uninstall extends UninstallAbstract
     /**
      * {@inheritdoc}
      */
-    public static function uninstall(Pool $dbPool, InfoManager $info)
+    public static function uninstall(DatabasePool $dbPool, InfoManager $info)
     {
         parent::uninstall($dbPool, $info);
 
diff --git a/Admin/Update.php b/Admin/Update.php
index 7f4a6e2..ab7048d 100644
--- a/Admin/Update.php
+++ b/Admin/Update.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -16,7 +16,7 @@
 namespace Modules\Calendar\Admin;
 
 
-use phpOMS\DataStorage\Database\Pool;
+use phpOMS\DataStorage\Database\DatabasePool;
 use phpOMS\Module\UpdateAbstract;
 use phpOMS\System\File\Directory;
 
@@ -37,7 +37,7 @@ class Update extends UpdateAbstract
     /**
      * {@inheritdoc}
      */
-    public static function update(Pool $dbPool, array $info)
+    public static function update(DatabasePool $dbPool, array $info)
     {
         Directory::deletePath(__DIR__ . '/Update');
         mkdir('Update');
diff --git a/Controller.php b/Controller.php
index 514650b..0c35341 100644
--- a/Controller.php
+++ b/Controller.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -47,7 +47,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string
      * @since 1.0.0
      */
-    const MODULE_PATH = __DIR__;
+    /* public */ const MODULE_PATH = __DIR__;
 
     /**
      * Module version.
@@ -55,7 +55,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string
      * @since 1.0.0
      */
-    const MODULE_VERSION = '1.0.0';
+    /* public */ const MODULE_VERSION = '1.0.0';
 
     /**
      * Module name.
@@ -63,7 +63,7 @@ class Controller extends ModuleAbstract implements WebInterface
      * @var string
      * @since 1.0.0
      */
-    const MODULE_NAME = 'Calendar';
+    /* public */ const MODULE_NAME = 'Calendar';
 
     /**
      * Providing.
diff --git a/Models/AcceptStatus.php b/Models/AcceptStatus.php
index dc60415..d0cca10 100644
--- a/Models/AcceptStatus.php
+++ b/Models/AcceptStatus.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,7 +30,7 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class AcceptStatus extends Enum
 {
-    const ACCEPTED = 0;
+    /* public */ const ACCEPTED = 0;
 
-    const DENIED = 1;
+    /* public */ const DENIED = 1;
 }
diff --git a/Models/AvailableStatus.php b/Models/AvailableStatus.php
index 1bd36ef..e6a753a 100644
--- a/Models/AvailableStatus.php
+++ b/Models/AvailableStatus.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,9 +30,9 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class AvailableStatus extends Enum
 {
-    const AVAILABLE = 0;
+    /* public */ const AVAILABLE = 0;
 
-    const BUSY = 1;
+    /* public */ const BUSY = 1;
 
-    const AWAY = 2;
+    /* public */ const AWAY = 2;
 }
diff --git a/Models/Calendar.php b/Models/Calendar.php
index 2f7f0b0..57c30bb 100644
--- a/Models/Calendar.php
+++ b/Models/Calendar.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Models/CalendarMapper.php b/Models/CalendarMapper.php
index 4e8b5b5..dcb685f 100644
--- a/Models/CalendarMapper.php
+++ b/Models/CalendarMapper.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -34,9 +34,9 @@ use phpOMS\DataStorage\Database\RelationType;
 class CalendarMapper extends DataMapperAbstract
 {
     /**
-     * Class name for .
+     * Class name.
      *
-     * @var array<string, array>
+     * @var string
      * @since 1.0.0
      */
     protected static $CLASS = __CLASS__;
@@ -44,7 +44,7 @@ class CalendarMapper extends DataMapperAbstract
     /**
      * Columns.
      *
-     * @var array<string, array>
+     * @var array
      * @since 1.0.0
      */
     protected static $columns = [
@@ -59,13 +59,12 @@ class CalendarMapper extends DataMapperAbstract
     /**
      * Has many relation.
      *
-     * @var array<string, array>
+     * @var array
      * @since 1.0.0
      */
     protected static $hasMany = [
         'events' => [
             'mapper'         => EventMapper::class,
-            'relationmapper' => EventMapper::class,
             'table'          => 'calendar_event',
             'dst'            => 'calendar_event_calendar',
             'src'            => null,
diff --git a/Models/Event.php b/Models/Event.php
index 0b9699e..da69ceb 100644
--- a/Models/Event.php
+++ b/Models/Event.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Models/EventMapper.php b/Models/EventMapper.php
index dec12bb..4b63357 100644
--- a/Models/EventMapper.php
+++ b/Models/EventMapper.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -37,7 +37,7 @@ class EventMapper extends DataMapperAbstract
     /**
      * Columns.
      *
-     * @var array<string, array>
+     * @var array
      * @since 1.0.0
      */
     protected static $columns = [
@@ -56,10 +56,10 @@ class EventMapper extends DataMapperAbstract
     /**
      * Has one relation.
      *
-     * @var array<string, array>
+     * @var array
      * @since 1.0.0
      */
-    protected static $hasOne = [
+    protected static $ownsOne = [
         'schedule' => [
             'mapper' => ScheduleMapper::class,
             'src'    => 'calendar_event_schedule',
diff --git a/Models/EventStatus.php b/Models/EventStatus.php
index 399861a..772c65d 100644
--- a/Models/EventStatus.php
+++ b/Models/EventStatus.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,5 +30,5 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class EventStatus extends Enum
 {
-    const ACTIVE = 1;
+    /* public */ const ACTIVE = 1;
 }
diff --git a/Models/EventTemplate.php b/Models/EventTemplate.php
index 81f073f..a3e7911 100644
--- a/Models/EventTemplate.php
+++ b/Models/EventTemplate.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Models/EventType.php b/Models/EventType.php
index 5a9bc3d..ee70765 100644
--- a/Models/EventType.php
+++ b/Models/EventType.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,7 +30,7 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class EventType extends Enum
 {
-    const TEMPLATE = 1;
+    /* public */ const TEMPLATE = 1;
 
-    const SINGLE = 2;
+    /* public */ const SINGLE = 2;
 }
diff --git a/Models/FrequencyInterval.php b/Models/FrequencyInterval.php
index d4ca6ea..95a0826 100644
--- a/Models/FrequencyInterval.php
+++ b/Models/FrequencyInterval.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,14 +30,14 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class FrequencyInterval extends Enum
 {
-    const SUNDAY     = 1;
-    const MONDAY     = 2;
-    const TUESDAY    = 4;
-    const WEDNESDAY  = 8;
-    const THURSDAY   = 16;
-    const FRIDAY     = 32;
-    const SATURDAY   = 64;
-    const DAY        = 128;
-    const WEEKDAY    = 256;
-    const WEEKENDDAY = 512;
+    /* public */ const SUNDAY     = 1;
+    /* public */ const MONDAY     = 2;
+    /* public */ const TUESDAY    = 4;
+    /* public */ const WEDNESDAY  = 8;
+    /* public */ const THURSDAY   = 16;
+    /* public */ const FRIDAY     = 32;
+    /* public */ const SATURDAY   = 64;
+    /* public */ const DAY        = 128;
+    /* public */ const WEEKDAY    = 256;
+    /* public */ const WEEKENDDAY = 512;
 }
diff --git a/Models/FrequencyRelative.php b/Models/FrequencyRelative.php
index 9f6754f..a1a5bf1 100644
--- a/Models/FrequencyRelative.php
+++ b/Models/FrequencyRelative.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,13 +30,13 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class FrequencyRelative extends Enum
 {
-    const FIRST = 1;
+    /* public */ const FIRST = 1;
 
-    const SECOND = 2;
+    /* public */ const SECOND = 2;
 
-    const THIRD = 4;
+    /* public */ const THIRD = 4;
 
-    const FOURTH = 8;
+    /* public */ const FOURTH = 8;
 
-    const LAST = 64;
+    /* public */ const LAST = 64;
 }
diff --git a/Models/FrequencyType.php b/Models/FrequencyType.php
index 11ca3c2..6cb1fc3 100644
--- a/Models/FrequencyType.php
+++ b/Models/FrequencyType.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,13 +30,13 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class FrequencyType extends Enum
 {
-    const ONCE = 1;
+    /* public */ const ONCE = 1;
 
-    const DAILY = 2;
+    /* public */ const DAILY = 2;
 
-    const WEEKLY = 4;
+    /* public */ const WEEKLY = 4;
 
-    const MONTHLY = 8;
+    /* public */ const MONTHLY = 8;
 
-    const YEARLY = 16;
+    /* public */ const YEARLY = 16;
 }
diff --git a/Models/IntervalType.php b/Models/IntervalType.php
index 87c0459..6fa0930 100644
--- a/Models/IntervalType.php
+++ b/Models/IntervalType.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,7 +30,7 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class IntervalType extends Enum
 {
-    const ABSOLUTE = 1;
+    /* public */ const ABSOLUTE = 1;
 
-    const RELATIVE = 2;
+    /* public */ const RELATIVE = 2;
 }
diff --git a/Models/NullCalendar.php b/Models/NullCalendar.php
index a659956..2904231 100644
--- a/Models/NullCalendar.php
+++ b/Models/NullCalendar.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Models/NullEvent.php b/Models/NullEvent.php
index e77a264..abc5248 100644
--- a/Models/NullEvent.php
+++ b/Models/NullEvent.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Models/NullSchedule.php b/Models/NullSchedule.php
new file mode 100644
index 0000000..3bf1d01
--- /dev/null
+++ b/Models/NullSchedule.php
@@ -0,0 +1,31 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.1
+ *
+ * @category   TBD
+ * @package    TBD
+ * @author     OMS Development Team <dev@oms.com>
+ * @author     Dennis Eichhorn <d.eichhorn@oms.com>
+ * @copyright  2013 Dennis Eichhorn
+ * @license    OMS License 1.0
+ * @version    1.0.0
+ * @link       http://orange-management.com
+ */
+namespace Modules\Calendar\Models;
+
+/**
+ * Schedule class.
+ *
+ * @category   Calendar
+ * @package    Modules
+ * @author     OMS Development Team <dev@oms.com>
+ * @author     Dennis Eichhorn <d.eichhorn@oms.com>
+ * @license    OMS License 1.0
+ * @link       http://orange-management.com
+ * @since      1.0.0
+ */
+class NullSchedule extends Schedule
+{
+}
diff --git a/Models/Schedule.php b/Models/Schedule.php
index 6c34965..67bc070 100644
--- a/Models/Schedule.php
+++ b/Models/Schedule.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Models/ScheduleMapper.php b/Models/ScheduleMapper.php
index 5fa5395..993178d 100644
--- a/Models/ScheduleMapper.php
+++ b/Models/ScheduleMapper.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -37,7 +37,7 @@ class ScheduleMapper extends DataMapperAbstract
     /**
      * Columns.
      *
-     * @var array<string, array>
+     * @var array
      * @since 1.0.0
      */
     protected static $columns = [
diff --git a/Models/ScheduleStatus.php b/Models/ScheduleStatus.php
index b90b5c8..9734714 100644
--- a/Models/ScheduleStatus.php
+++ b/Models/ScheduleStatus.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
@@ -30,6 +30,6 @@ use phpOMS\Datatypes\Enum;
  */
 abstract class ScheduleStatus extends Enum
 {
-    const ACTIVE   = 1;
-    const INACTIVE = 1;
+    /* public */ const ACTIVE   = 1;
+    /* public */ const INACTIVE = 1;
 }
diff --git a/Theme/Backend/Lang/Navigation.en.lang.php b/Theme/Backend/Lang/Navigation.en.lang.php
index b79eb56..17b9e61 100644
--- a/Theme/Backend/Lang/Navigation.en.lang.php
+++ b/Theme/Backend/Lang/Navigation.en.lang.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Theme/Backend/Lang/api.en.lang.php b/Theme/Backend/Lang/api.en.lang.php
index 4f9f946..afe845f 100644
--- a/Theme/Backend/Lang/api.en.lang.php
+++ b/Theme/Backend/Lang/api.en.lang.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Theme/Backend/Lang/en.lang.php b/Theme/Backend/Lang/en.lang.php
index b8b2849..b69a962 100644
--- a/Theme/Backend/Lang/en.lang.php
+++ b/Theme/Backend/Lang/en.lang.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Theme/Backend/calendar-dashboard.tpl.php b/Theme/Backend/calendar-dashboard.tpl.php
index 2c21033..3f4ad3b 100644
--- a/Theme/Backend/calendar-dashboard.tpl.php
+++ b/Theme/Backend/calendar-dashboard.tpl.php
@@ -23,7 +23,7 @@ $calendar = $this->getData('calendar');
                     <?php if($calendar->getDate()->getFirstDayOfMonth() <= $i*7+$j+1 && $calendar->getDate()->getDaysOfMonth() >= $i*7+$j+1) {
                         echo ($i*7+$j+1) . ' ' . jddayofweek($j, 1);
                     } else {
-                        echo (($i*7+$j+1)-$calendar->getDate()->getDaysOfMonth()) . ' ' . jddayofweek($j, 1);
+                        echo $current->createModify(0, 0, -2)->format('d') . ' ' . jddayofweek($j, 1);
                     } ?>
                         <ul>
                         <?php
diff --git a/Theme/backend/Lang/Navigation.en.lang.php b/Theme/backend/Lang/Navigation.en.lang.php
index b79eb56..17b9e61 100644
--- a/Theme/backend/Lang/Navigation.en.lang.php
+++ b/Theme/backend/Lang/Navigation.en.lang.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Theme/backend/Lang/api.en.lang.php b/Theme/backend/Lang/api.en.lang.php
index 4f9f946..afe845f 100644
--- a/Theme/backend/Lang/api.en.lang.php
+++ b/Theme/backend/Lang/api.en.lang.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Theme/backend/Lang/en.lang.php b/Theme/backend/Lang/en.lang.php
index b8b2849..b69a962 100644
--- a/Theme/backend/Lang/en.lang.php
+++ b/Theme/backend/Lang/en.lang.php
@@ -2,7 +2,7 @@
 /**
  * Orange Management
  *
- * PHP Version 7.0
+ * PHP Version 7.1
  *
  * @category   TBD
  * @package    TBD
diff --git a/Theme/backend/calendar-dashboard.tpl.php b/Theme/backend/calendar-dashboard.tpl.php
index 2c21033..3f4ad3b 100644
--- a/Theme/backend/calendar-dashboard.tpl.php
+++ b/Theme/backend/calendar-dashboard.tpl.php
@@ -23,7 +23,7 @@ $calendar = $this->getData('calendar');
                     <?php if($calendar->getDate()->getFirstDayOfMonth() <= $i*7+$j+1 && $calendar->getDate()->getDaysOfMonth() >= $i*7+$j+1) {
                         echo ($i*7+$j+1) . ' ' . jddayofweek($j, 1);
                     } else {
-                        echo (($i*7+$j+1)-$calendar->getDate()->getDaysOfMonth()) . ' ' . jddayofweek($j, 1);
+                        echo $current->createModify(0, 0, -2)->format('d') . ' ' . jddayofweek($j, 1);
                     } ?>
                         <ul>
                         <?php