diff --git a/application/controllers/api/frontend/v1/tempus/Config.php b/application/controllers/api/frontend/v1/tempus/Config.php
index 27a4958cb..a79af95cb 100644
--- a/application/controllers/api/frontend/v1/tempus/Config.php
+++ b/application/controllers/api/frontend/v1/tempus/Config.php
@@ -56,6 +56,7 @@ class Config extends FHCAPI_Controller
 
 		$this->_ci->KalenderStatusModel->addSelect('*, array_to_json(bezeichnung_mehrsprachig::varchar[])->>' . $language .' AS status');
 		$this->_ci->KalenderStatusModel->addOrder('sort');
+		$this->_ci->KalenderStatusModel->db->where_not_in('status_kurzbz', array('archived', 'deleted'));
 		$visible_status = $this->_ci->KalenderStatusModel->load();
 
 		$visible_status = getData($visible_status);
diff --git a/application/controllers/api/frontend/v1/tempus/Kalender.php b/application/controllers/api/frontend/v1/tempus/Kalender.php
index ca8471a9a..b0f1bcfda 100644
--- a/application/controllers/api/frontend/v1/tempus/Kalender.php
+++ b/application/controllers/api/frontend/v1/tempus/Kalender.php
@@ -14,17 +14,22 @@ class Kalender extends FHCAPI_Controller
 	 */
 	public function __construct()
 	{
-
 		parent::__construct([
 			'getStunden' => self::PERM_LOGGED,
 			'getPlan' => self::PERM_LOGGED,
-			'getPlanNew' => self::PERM_LOGGED,
 			'getPlanByOrt' => self::PERM_LOGGED,
 			'getRaumvorschlag' => self::PERM_LOGGED,
+			'getHistory' => 'lehre/lvplan:rw',
+			'deleteEntry' => 'lehre/lvplan:rw',
+			'syncToLecturer' => 'lehre/lvplan:rw',
+			'syncToStudent' => 'lehre/lvplan:rw',
+			'getPlanLecturer' =>'lehre/lvplan:rw',
+			'getPlanStudent' => 'lehre/lvplan:rw',
 			'getZeitwuensche' => self::PERM_LOGGED,
 			'getZeitsperren' => self::PERM_LOGGED,
 			'updateKalenderEvent' => 'lehre/lvplan:rw',
-			'addKalenderEvent' => 'lehre/lvplan:rw'
+			'addKalenderEvent' => 'lehre/lvplan:rw',
+			'sync' => 'lehre/lvplan:rw',
 		]);
 
 		$this->_ci =& get_instance();
@@ -64,6 +69,7 @@ class Kalender extends FHCAPI_Controller
 
 		$this->terminateWithSuccess($stunden);
 	}
+
 	public function getPlan()
 	{
 		$this->_ci->form_validation->set_data($_GET);
@@ -78,7 +84,7 @@ class Kalender extends FHCAPI_Controller
 
 		$filter = $this->_checkFilter(self::ALLOWED_PLAN_FILTER);
 
-		$stundenplan_data = $this->_ci->kalenderlib->getPlan(
+		$stundenplan_data = $this->_ci->kalenderlib->getPlanForPlanner(
 			$start_date,
 			$end_date,
 			isset($filter->ort) ? $filter->ort : null,
@@ -89,7 +95,7 @@ class Kalender extends FHCAPI_Controller
 		$this->terminateWithSuccess($stundenplan_data);
 	}
 
-	public function getPlanNew()
+	public function getPlanStudent()
 	{
 		$this->_ci->form_validation->set_data($_GET);
 		$this->_ci->form_validation->set_rules('start_date',"start_date","required");
@@ -101,14 +107,29 @@ class Kalender extends FHCAPI_Controller
 		$start_date = $this->_ci->input->get('start_date', TRUE);
 		$end_date = $this->_ci->input->get('end_date', TRUE);
 
-		$filter = $this->_checkFilter(self::ALLOWED_PLAN_FILTER);
-
-		$stundenplan_data = $this->_ci->kalenderlib->getPlanNew(
+		$stundenplan_data = $this->_ci->kalenderlib->getPlanForStudent(
 			$start_date,
-			$end_date,
-			isset($filter->ort) ? $filter->ort : null,
-			isset($filter->uid) ? $filter->uid : null,
-			isset($filter->stg) ? $filter->stg : null
+			$end_date
+		);
+
+		$this->terminateWithSuccess($stundenplan_data);
+	}
+
+	public function getPlanLecturer()
+	{
+		$this->_ci->form_validation->set_data($_GET);
+		$this->_ci->form_validation->set_rules('start_date',"start_date","required");
+		$this->_ci->form_validation->set_rules('end_date',"end_date","required");
+
+		if($this->_ci->form_validation->run() === FALSE)
+			$this->terminateWithValidationErrors($this->_ci->form_validation->error_array());
+
+		$start_date = $this->_ci->input->get('start_date', TRUE);
+		$end_date = $this->_ci->input->get('end_date', TRUE);
+
+		$stundenplan_data = $this->_ci->kalenderlib->getPlanForLecturer(
+			$start_date,
+			$end_date
 		);
 
 		$this->terminateWithSuccess($stundenplan_data);
@@ -238,6 +259,81 @@ class Kalender extends FHCAPI_Controller
 		$this->terminateWithSuccess(getData($result));
 	}
 
+	public function getHistory()
+	{
+		$this->_ci->form_validation->set_data($_GET);
+		$this->_ci->form_validation->set_rules('kalender_id',"kalender_id","required");
+
+		if($this->_ci->form_validation->run() === FALSE)
+			$this->terminateWithValidationErrors($this->_ci->form_validation->error_array());
+
+		$kalender_id = $this->_ci->input->get('kalender_id', TRUE);
+
+		$result = $this->_ci->kalenderlib->getHistory($kalender_id);
+
+		if (isError($result))
+			$this->terminateWithError(getError($result));
+
+		$this->terminateWithSuccess(getData($result));
+	}
+
+	public function deleteEntry()
+	{
+		$this->_ci->form_validation->set_data($_POST);
+		$this->_ci->form_validation->set_rules('kalender_id', "kalender_id", "required");
+
+		if($this->_ci->form_validation->run() === FALSE)
+			$this->terminateWithValidationErrors($this->_ci->form_validation->error_array());
+
+		$kalender_id = $this->_ci->input->post('kalender_id', TRUE);
+
+		$result = $this->_ci->kalenderlib->deleteEntry($kalender_id);
+
+		if (isError($result))
+			$this->terminateWithError(getError($result));
+
+		$this->terminateWithSuccess($result);
+	}
+
+	public function sync()
+	{
+		$result = $this->_ci->kalenderlib->sync();
+		$this->terminateWithSuccess($result);
+	}
+	public function syncToLecturer()
+	{
+		$this->_ci->form_validation->set_data($_POST);
+		$this->_ci->form_validation->set_rules('kalender_id', "kalender_id", "required");
+
+		if($this->_ci->form_validation->run() === FALSE)
+			$this->terminateWithValidationErrors($this->_ci->form_validation->error_array());
+
+		$kalender_id = $this->_ci->input->post('kalender_id', TRUE);
+
+		$result = $this->_ci->kalenderlib->updateStatus($kalender_id, 'tosync_lektor');
+
+		if (isError($result))
+			$this->terminateWithError(getError($result));
+
+		$this->terminateWithSuccess($result);
+	}
+	public function syncToStudent()
+	{
+		$this->_ci->form_validation->set_data($_POST);
+		$this->_ci->form_validation->set_rules('kalender_id', "kalender_id", "required");
+
+		if($this->_ci->form_validation->run() === FALSE)
+			$this->terminateWithValidationErrors($this->_ci->form_validation->error_array());
+
+		$kalender_id = $this->_ci->input->post('kalender_id', TRUE);
+
+		$result = $this->_ci->kalenderlib->updateStatus($kalender_id, 'tosync_student');
+
+		if (isError($result))
+			$this->terminateWithError(getError($result));
+
+		$this->terminateWithSuccess($result);
+	}
 	public function addKalenderEvent()
 	{
 		$this->_ci->form_validation->set_data($_POST);
diff --git a/application/controllers/jobs/TempusJob.php b/application/controllers/jobs/TempusJob.php
new file mode 100644
index 000000000..92901aa33
--- /dev/null
+++ b/application/controllers/jobs/TempusJob.php
@@ -0,0 +1,27 @@
+<?php
+
+if (!defined("BASEPATH")) exit("No direct script access allowed");
+
+class TempusJob extends JOB_Controller
+{
+	private $_ci;
+
+	public function __construct()
+	{
+		parent::__construct();
+
+		$this->_ci =& get_instance();
+
+		$this->_ci->load->helper('hlp_sancho_helper');
+		$this->_ci->load->library('KalenderLib');
+	}
+
+
+	public function sync()
+	{
+		$this->_ci->logInfo('Start job FHC-Core->Tempus->sync');
+		$this->_ci->kalenderlib->sync();
+		$this->_ci->logInfo('End job FHC-Core->Tempus->sync');
+	}
+
+}
diff --git a/application/libraries/KalenderLib.php b/application/libraries/KalenderLib.php
index 5e33d40e1..b4799cc6c 100644
--- a/application/libraries/KalenderLib.php
+++ b/application/libraries/KalenderLib.php
@@ -38,7 +38,7 @@ class KalenderLib
 												lehrfach.farbe,
 												tbl_lehreinheitmitarbeiter.mitarbeiter_uid,
 												tbl_person.vorname,
-												tbl_paddKalenderEventerson.nachname,
+												tbl_person.nachname,
 												tbl_mitarbeiter.kurzbz AS ma_kurzbz');
 		$this->_ci->KalenderModel->addJoin('lehre.tbl_kalender_lehreinheit', 'tbl_kalender.kalender_id = tbl_kalender_lehreinheit.kalender_id');
 		$this->_ci->KalenderModel->addJoin('lehre.tbl_lehreinheit', 'tbl_kalender_lehreinheit.lehreinheit_id = tbl_lehreinheit.lehreinheit_id');
@@ -186,7 +186,7 @@ class KalenderLib
 		return $this->_ci->OrtModel->load();
 	}
 
-	public function getPlanNew($start_date, $end_date, $ort = null, $uids = null, $stg = null)
+	public function getPlanForPlanner($start_date, $end_date, $ort = null, $uids = null, $stg = null)
 	{
 		$this->_getBasePlan($start_date, $end_date);
 
@@ -199,114 +199,55 @@ class KalenderLib
 		if (!is_null($stg))
 			$this->_ci->KalenderModel->db->where('tbl_lehrveranstaltung.studiengang_kz', $stg);
 
+		$this->_ci->KalenderModel->db->where('NOT EXISTS (
+				SELECT 1 FROM lehre.tbl_kalender nachfolger
+				WHERE nachfolger.vorgaenger_kalender_id = tbl_kalender.kalender_id)', null, false);
+
+		$this->_ci->KalenderModel->db->where_not_in('status_kurzbz', array('deleted'));
 		$data = $this->_ci->KalenderModel->load();
 
 		return $this->_mapEvents($data);
 	}
-	public function getPlan($start_date, $end_date, $ort = null, $uids = null, $stg = null)
+
+	public function getPlanForStudent($start_date, $end_date)
 	{
-		$end_date = date('Y-m-d', strtotime($end_date . ' +1 day'));
+		$this->_getBasePlan($start_date, $end_date);
 
-		$this->_ci->KalenderModel->addSelect('tbl_kalender.kalender_id,
-												tbl_kalender.status_kurzbz,
-												tbl_kalender.von,
-												tbl_kalender.bis,
-												tbl_kalender_ort.ort_kurzbz,
-												tbl_lehreinheit.lehreinheit_id,
-												tbl_lehreinheit.lehrveranstaltung_id,
-												tbl_lehreinheit.lehrfach_id,
-												tbl_lehreinheit.lehrform_kurzbz,
-												tbl_lehrveranstaltung.oe_kurzbz,
-												lehrfach.kurzbz AS lehrfach_kurzbz,
-												lehrfach.bezeichnung AS lehrfach_bezeichnung,
-												lehrfach.farbe,
-												tbl_lehreinheitmitarbeiter.mitarbeiter_uid,
-												tbl_person.vorname,
-												tbl_person.nachname,
-												tbl_mitarbeiter.kurzbz AS ma_kurzbz');
-		$this->_ci->KalenderModel->addJoin('lehre.tbl_kalender_lehreinheit', 'tbl_kalender.kalender_id = tbl_kalender_lehreinheit.kalender_id');
-		$this->_ci->KalenderModel->addJoin('lehre.tbl_lehreinheit', 'tbl_kalender_lehreinheit.lehreinheit_id = tbl_lehreinheit.lehreinheit_id');
-		$this->_ci->KalenderModel->addJoin('lehre.tbl_lehrveranstaltung', 'tbl_lehreinheit.lehrveranstaltung_id = tbl_lehrveranstaltung.lehrveranstaltung_id');
-		$this->_ci->KalenderModel->addJoin('lehre.tbl_lehrveranstaltung lehrfach', 'tbl_lehreinheit.lehrfach_id = lehrfach.lehrveranstaltung_id', 'LEFT');
-		$this->_ci->KalenderModel->addJoin('lehre.tbl_kalender_ort', 'tbl_kalender.kalender_id = tbl_kalender_ort.kalender_id', 'LEFT');
-		$this->_ci->KalenderModel->addJoin('lehre.tbl_lehreinheitmitarbeiter', 'tbl_lehreinheit.lehreinheit_id = tbl_lehreinheitmitarbeiter.lehreinheit_id', 'LEFT');
-		$this->_ci->KalenderModel->addJoin('public.tbl_mitarbeiter', 'tbl_mitarbeiter.mitarbeiter_uid = tbl_lehreinheitmitarbeiter.mitarbeiter_uid', 'LEFT');
-		$this->_ci->KalenderModel->addJoin('public.tbl_benutzer', 'tbl_mitarbeiter.mitarbeiter_uid = tbl_benutzer.uid', 'LEFT');
-		$this->_ci->KalenderModel->addJoin('public.tbl_person', 'tbl_person.person_id = tbl_benutzer.person_id', 'LEFT');
-
-		$this->_ci->KalenderModel->db->where('tbl_kalender.von >=', $start_date);
-		$this->_ci->KalenderModel->db->where('tbl_kalender.bis <', $end_date);
-
-		if (!is_null($ort))
-			$this->_ci->KalenderModel->db->where('tbl_kalender_ort.ort_kurzbz', $ort);
-
-		if (!is_null($uids))
-			$this->_ci->KalenderModel->db->where_in('tbl_lehreinheitmitarbeiter.mitarbeiter_uid', $uids);
-
-		if (!is_null($stg))
-			$this->_ci->KalenderModel->db->where('tbl_lehrveranstaltung.studiengang_kz', $stg);
+		$this->_ci->KalenderModel->db->where('status_kurzbz', 'visible_student');
 
 		$data = $this->_ci->KalenderModel->load();
 
-		$stundenplan_data = [];
+		return $this->_mapEvents($data);
+	}
 
-		if (!isSuccess($data) || !hasData($data))
-			return $stundenplan_data;
 
-		$events = [];
+	public function getPlanForLecturer($start_date, $end_date)
+	{
+		$this->_getBasePlan($start_date, $end_date);
 
-		foreach (getData($data) as $row)
-		{
-			$id = $row->kalender_id;
+		$this->_ci->KalenderModel->addJoin(
+			'lehre.tbl_kalender neuerer',
+			"neuerer.vorgaenger_kalender_id = tbl_kalender.kalender_id AND neuerer.status_kurzbz IN ('visible_lektor', 'tosync_student')",
+			'LEFT'
+		);
+		$this->_ci->KalenderModel->db->where("(
+			tbl_kalender.status_kurzbz = 'tosync_student'
+			OR (tbl_kalender.status_kurzbz = 'visible_lektor' AND neuerer.kalender_id IS NULL)
+			OR (tbl_kalender.status_kurzbz = 'visible_student' AND neuerer.kalender_id IS NULL)
+		)", NULL, FALSE);
+		$data = $this->_ci->KalenderModel->load();
 
-			if (!isset($events[$id]))
-			{
-				$von = new DateTime($row->von);
-				$bis = new DateTime($row->bis);
+		return $this->_mapEvents($data);
+	}
+	public function getPlanForLecturer2($start_date, $end_date)
+	{
+		$this->_getBasePlan($start_date, $end_date);
 
-				$events[$id] = (object) [
-					'type' => 'lehreinheit',
-					'beginn' => $von->format('H:i:s'),
-					'ende' => $bis->format('H:i:s'),
-					'datum' => $von->format('Y-m-d'),
-					'isostart' => $von->format('c'),
-					'isoend' => $bis->format('c'),
-					'tooltip' => 'tip',
-					'status_kurzbz' => $row->status_kurzbz,
-					'ort_kurzbz' => isset($row->ort_kurzbz) ? $row->ort_kurzbz : '',
-					'lehrform' => isset($row->lehrform_kurzbz) ? $row->lehrform_kurzbz : '',
-					'lehrfach' => isset($row->lehrfach_kurzbz) ? $row->lehrfach_kurzbz : '',
-					'lehrfach_bez' => isset($row->lehrfach_bezeichnung) ? $row->lehrfach_bezeichnung : '',
-					'farbe' => isset($row->farbe) ? $row->farbe : '',
-					'lehrveranstaltung_id' => $row->lehrveranstaltung_id,
-					'organisationseinheit' => isset($row->oe_kurzbz) ? $row->oe_kurzbz : '',
-					'kalender_id' => $id,
-					'lehreinheit_id' => [],
-					'lektor' => [],
-					'gruppe' => [],
-					'titel' => '',
-					'topic' => (isset($row->lehrfach_kurzbz) ? $row->lehrfach_kurzbz : '') . ' ' . (isset($row->lehrform_kurzbz) ? $row->lehrform_kurzbz : ''),
-				];
-			}
+		$this->_ci->KalenderModel->db->where_in('status_kurzbz', array('visible_student', 'visible_lektor'));
 
-			if ($row->lehreinheit_id && !in_array($row->lehreinheit_id, $events[$id]->lehreinheit_id))
-				$events[$id]->lehreinheit_id[] = $row->lehreinheit_id;
+		$data = $this->_ci->KalenderModel->load();
 
-			if ($row->mitarbeiter_uid)
-			{
-				if (!in_array($row->mitarbeiter_uid, array_column($events[$id]->lektor, 'mitarbeiter_uid')))
-				{
-					$events[$id]->lektor[] = [
-						'mitarbeiter_uid' => $row->mitarbeiter_uid,
-						'vorname' => $row->vorname,
-						'nachname' => $row->nachname,
-						'kurzbz' => $row->ma_kurzbz,
-					];
-				}
-			}
-		}
-
-		return array_values($events);
+		return $this->_mapEvents($data);
 	}
 	public function getZeitsperren($start_date, $end_date, $emp)
 	{
@@ -456,42 +397,336 @@ class KalenderLib
 		);
 	}
 
+	public function updateZeit($kalender_id, $start_date, $end_date)
+	{
+		$entryResult = $this->_loadKalenderEntry($kalender_id);
+		if (isError($entryResult)) return $entryResult;
+
+		$kalender_entry = getData($entryResult);
+
+		if (in_array($kalender_entry->status_kurzbz, array('todelete', 'deleted')))
+			return error('Eintrag kann nicht mehr bearbeitet werden');
+
+		if (in_array($kalender_entry->status_kurzbz, array('visible_student', 'visible_lektor')))
+			return $this->_createHistoryEntry($kalender_entry, $start_date, $end_date);
+
+		return $this->_ci->KalenderModel->update(
+			array('kalender_id' => $kalender_id),
+			array(
+				'von' => $start_date,
+				'bis' => $end_date,
+				'updateamum' => date('Y-m-d H:i:s'),
+				'updatevon' => getAuthUID()
+			)
+		);
+	}
+
 	public function updateOrt($kalender_id, $ort_kurzbz)
 	{
-		$exist = $this->_ci->KalenderOrtModel->load(array('kalender_id' => $kalender_id));
+		$entryResult = $this->_loadKalenderEntry($kalender_id);
+		if (isError($entryResult)) return $entryResult;
 
+		$kalender_entry = getData($entryResult);
+
+		if (in_array($kalender_entry->status_kurzbz, array('todelete', 'deleted')))
+			return error('Eintrag kann nicht mehr bearbeitet werden');
+
+		if (in_array($kalender_entry->status_kurzbz, array('visible_student', 'visible_lektor')))
+			return $this->_createHistoryEntry($kalender_entry, null, null, $ort_kurzbz);
+
+		$exist = $this->_ci->KalenderOrtModel->load(array('kalender_id' => $kalender_id));
 		if (hasData($exist))
 		{
-			return $this->_ci->KalenderOrtModel->update(array('kalender_id' => $kalender_id),
-				array (
-					'ort_kurzbz' => $ort_kurzbz
-				)
+			return $this->_ci->KalenderOrtModel->update(
+				array('kalender_id' => $kalender_id),
+				array('ort_kurzbz' => $ort_kurzbz)
 			);
 		}
 		else
 		{
 			return $this->_addKalenderOrt($kalender_id, $ort_kurzbz);
 		}
-
 	}
-	public function updateZeit($kalender_id, $start_date, $end_date)
-	{
-		/*TODO Checks:
-		Von-Tag muss gleich dem Bis-Tag sein
-		Bis darf nicht vor von liegen
 
-		History erstellen
-		Sync Status setzen
-		*/
-		$this->_ci->KalenderModel->update($kalender_id,
-			array (
-				'von' => $start_date,
-				'bis' => $end_date,
-				'updateamum'=> date('Y-m-d H:i:s'),
-				'updatevon' => getAuthUID()
-			)
+	public function updateStatus($kalender_id, $status_kurzbz)
+	{
+		$entryResult = $this->_loadKalenderEntry($kalender_id);
+		if (isError($entryResult)) return $entryResult;
+
+		$kalender_entry = getData($entryResult);
+
+		$allowed = array(
+			'planning' => array('tosync_lektor', 'tosync_student'),
+			'tosync_lektor' => array('tosync_student'),
+			'tosync_student' => array('tosync_lektor'),
+			'visible_lektor' => array('tosync_student'),
 		);
 
+		if (!isset($allowed[$kalender_entry->status_kurzbz]) || !in_array($status_kurzbz, $allowed[$kalender_entry->status_kurzbz]))
+			return error('Statuswechsel nicht erlaubt');
+
+		$result = $this->_ci->KalenderModel->update(
+			array('kalender_id' => $kalender_entry->kalender_id),
+			array('status_kurzbz' => $status_kurzbz)
+		);
+
+		if (isError($result)) return $result;
+
 		return success();
 	}
+
+	private function _createHistoryEntry($kalender_entry, $start_date = null, $end_date = null, $ort_kurzbz = null)
+	{
+		$old_id = $kalender_entry->kalender_id;
+
+		$kalenderresult = $this->_ci->KalenderModel->insert(
+			array(
+				'von' => $start_date ? $start_date : $kalender_entry->von,
+				'bis' => $end_date ? $end_date : $kalender_entry->bis,
+				'typ' => 'lehreinheit',
+				'status_kurzbz' => 'planning',
+				'vorgaenger_kalender_id' => $old_id,
+				'insertvon' => getAuthUID(),
+				'insertamum' => date('Y-m-d H:i:s')
+			)
+		);
+
+		if (!isSuccess($kalenderresult) || !hasData($kalenderresult))
+			return $kalenderresult;
+
+		$new_kalender_id = getData($kalenderresult);
+
+		$kalenderlehreinheitresult = $this->_ci->KalenderLehreinheitModel->insert(
+			array(
+				'kalender_id' => $new_kalender_id,
+				'lehreinheit_id' => $kalender_entry->lehreinheit_id
+			)
+		);
+
+		if (!isSuccess($kalenderlehreinheitresult))
+			return $kalenderlehreinheitresult;
+
+		$new_ort = $ort_kurzbz ? $ort_kurzbz : $kalender_entry->ort_kurzbz;
+		if (!is_null($new_ort) || !is_null($kalender_entry->location))
+		{
+			$ortresult = $this->_ci->KalenderOrtModel->insert(
+				array(
+					'kalender_id' => $new_kalender_id,
+					'ort_kurzbz' => $new_ort,
+					'location' => $kalender_entry->location
+				)
+			);
+
+			if (!isSuccess($ortresult))
+				return $ortresult;
+		}
+
+		return success($new_kalender_id);
+	}
+
+	private function _loadKalenderEntry($kalender_id)
+	{
+		$this->_ci->KalenderModel->addSelect('tbl_kalender.*, tbl_kalender_lehreinheit.lehreinheit_id, tbl_kalender_ort.ort_kurzbz, tbl_kalender_ort.location');
+		$this->_ci->KalenderModel->addJoin('lehre.tbl_kalender_lehreinheit', 'tbl_kalender.kalender_id = tbl_kalender_lehreinheit.kalender_id');
+		$this->_ci->KalenderModel->addJoin('lehre.tbl_kalender_ort', 'tbl_kalender.kalender_id = tbl_kalender_ort.kalender_id', 'LEFT');
+
+		$result = $this->_ci->KalenderModel->load(array('tbl_kalender.kalender_id' => $kalender_id));
+
+		if (isError($result)) return $result;
+		if (!hasData($result)) return error("Not found");
+
+		return success(getData($result)[0]);
+	}
+
+
+
+	public function deleteEntry($kalender_id)
+	{
+		$result = $this->_ci->KalenderModel->load(array('tbl_kalender.kalender_id' => $kalender_id));
+
+		if (isError($result)) return $result;
+
+		if (!hasData($result)) return error("Not found");
+
+		$entry = getData($result)[0];
+
+		if ($entry->typ === 'lehreinheit')
+			return $this->_deleteTypLehreinheit($entry);
+	}
+
+	private function _deleteTypLehreinheit($entry)
+	{
+		$result_lehreinheit = $this->_ci->KalenderLehreinheitModel->loadWhere(array('kalender_id' => $entry->kalender_id));
+		if (isError($result_lehreinheit)) return $result_lehreinheit;
+		$has_lehreinheit = hasData($result_lehreinheit) ? getData($result_lehreinheit)[0] : false;
+
+		$result_ort = $this->_ci->KalenderOrtModel->loadWhere(array('kalender_id' => $entry->kalender_id));
+		if (isError($result_ort)) return $result_ort;
+		$has_ort = hasData($result_ort) ? getData($result_ort)[0] : false;
+
+		if ($entry->status_kurzbz === 'planning')
+		{
+			if ($has_ort)
+				$this->_deleteOrtEntry($has_ort);
+
+			if ($has_lehreinheit)
+				$this->_deleteLehreinheitEntry($has_lehreinheit);
+
+			$this->_ci->KalenderModel->delete(array('tbl_kalender.kalender_id' => $entry->kalender_id));
+		}
+		else if ($entry->status_kurzbz === 'tosync_lektor' || $entry->status_kurzbz === 'tosync_student')
+		{
+			$history = $this->getHistory($entry->kalender_id);
+			$history = hasData($history) ? getData($history) : false;
+
+			if ($has_ort)
+				$result = $this->_deleteOrtEntry($has_ort);
+
+			if ($has_lehreinheit)
+				$result = $this->_deleteLehreinheitEntry($has_lehreinheit);
+
+			$this->_ci->KalenderModel->delete(array('tbl_kalender.kalender_id' => $entry->kalender_id));
+		}
+		else if ($entry->status_kurzbz === 'visible_lektor' || $entry->status_kurzbz === 'visible_student')
+		{
+			//TODO (david) überprüfen ob sinnvoll, verschwindet direkt in den ansichten (student, lecturer)
+			$result = $this->_ci->KalenderModel->update(
+				array('kalender_id' => $entry->kalender_id),
+				array('status_kurzbz' => 'todelete')
+			);
+		}
+
+		return success();
+	}
+
+	private function _deleteOrtEntry($entry)
+	{
+		return $this->_ci->KalenderOrtModel->delete(array('kalender_id' => $entry->kalender_id));
+
+	}
+
+	private function _deleteLehreinheitEntry($entry)
+	{
+		return $this->_ci->KalenderLehreinheitModel->delete(array('kalender_id' => $entry->kalender_id));
+	}
+
+	public function getHistory($kalender_id, $only_previous = false)
+	{
+		$dbModel = new DB_Model();
+		$history_entries = $dbModel->execReadOnlyQuery('
+				WITH RECURSIVE 
+				vorgaenger(kalender_id, vorgaenger_kalender_id) AS (
+					SELECT kalender_id, vorgaenger_kalender_id
+					FROM lehre.tbl_kalender
+					WHERE kalender_id = ?
+			
+					UNION ALL
+			
+					SELECT k.kalender_id, k.vorgaenger_kalender_id
+					FROM lehre.tbl_kalender k
+					JOIN vorgaenger ON k.kalender_id = vorgaenger.vorgaenger_kalender_id
+				),
+				nachfolger(kalender_id, vorgaenger_kalender_id) AS (
+					SELECT kalender_id, vorgaenger_kalender_id
+					FROM lehre.tbl_kalender
+					WHERE kalender_id = ?
+			
+					UNION ALL
+			
+					SELECT k.kalender_id, k.vorgaenger_kalender_id
+					FROM lehre.tbl_kalender k
+					JOIN nachfolger ON k.vorgaenger_kalender_id = nachfolger.kalender_id
+				)
+				SELECT tbl_kalender.*,
+						TO_CHAR(von, \'DD.MM.YYYY HH24:MI:SS\') as von,
+						TO_CHAR(bis, \'DD.MM.YYYY HH24:MI:SS\') as bis,
+						COALESCE(tbl_kalender_ort.ort_kurzbz, location) as ort
+				FROM (
+					SELECT kalender_id FROM vorgaenger
+					UNION
+					SELECT kalender_id FROM nachfolger
+				) combined
+				JOIN lehre.tbl_kalender USING(kalender_id)
+				LEFT JOIN lehre.tbl_kalender_ort USING(kalender_id)
+				ORDER BY kalender_id DESC
+				
+			' . ($only_previous ? ' LIMIT 1' : ''), array($kalender_id, $kalender_id));
+
+		return $history_entries;
+	}
+
+	//TODO in eine eigen Lib?
+	public function sync()
+	{
+
+		$this->_ci->load->model('ressource/Kalender_model', 'KalenderModel');
+
+		$this->_ci->KalenderModel->db->where_in('status_kurzbz', array('tosync_student', 'tosync_lektor', 'todelete', 'planning', 'visible_lektor'));
+		$this->_ci->KalenderModel->addOrder('kalender_id', 'DESC');
+		$to_update = $this->_ci->KalenderModel->load();
+
+		if (!hasData($to_update))
+			return success();
+		foreach (getData($to_update) as $entry)
+		{
+			if ($entry->status_kurzbz === 'todelete')
+			{
+				$this->_ci->KalenderModel->update(array('kalender_id' => $entry->kalender_id), array('status_kurzbz' => 'deleted'));
+			}
+			if ($entry->status_kurzbz === 'tosync_lektor')
+			{
+				$this->_ci->KalenderModel->update(array('kalender_id' => $entry->kalender_id), array('status_kurzbz' => 'visible_lektor'));
+				$this->_archiveVorgaenger($entry->vorgaenger_kalender_id, true);
+			}
+
+			if ($entry->status_kurzbz === 'tosync_student' || $entry->status_kurzbz === 'planning')
+			{
+				$this->_ci->KalenderModel->update(array('kalender_id' => $entry->kalender_id), array('status_kurzbz' => 'visible_student'));
+				$this->_archiveVorgaenger($entry->vorgaenger_kalender_id, false);
+			}
+
+			if ($entry->status_kurzbz === 'visible_lektor')
+			{
+				$current = getData($this->_ci->KalenderModel->load(array('kalender_id' => $entry->kalender_id)))[0];
+				if ($current->status_kurzbz === 'archived')
+					continue;
+
+				$this->_ci->KalenderModel->update(array('kalender_id' => $entry->kalender_id), array('status_kurzbz' => 'visible_student'));
+				$this->_archiveVorgaenger($entry->vorgaenger_kalender_id, false);
+			}
+		}
+
+		return success();
+
+
+	}
+
+	private function _archiveVorgaenger($vorgaenger_kalender_id, $stop_at_visible_student = false)
+	{
+		if (!$vorgaenger_kalender_id) return;
+
+		$current_id = $vorgaenger_kalender_id;
+
+		while ($current_id)
+		{
+			$vorgaenger = $this->_ci->KalenderModel->load(array('kalender_id' => $current_id));
+			if (!hasData($vorgaenger)) return;
+
+			$vorgaenger = getData($vorgaenger)[0];
+
+			if ($stop_at_visible_student && $vorgaenger->status_kurzbz === 'visible_student')
+				return;
+
+			if (in_array($vorgaenger->status_kurzbz, array('visible_lektor', 'visible_student')))
+			{
+				$this->_ci->KalenderModel->update(
+					array('kalender_id' => $current_id),
+					array('status_kurzbz' => 'archived')
+				);
+			}
+
+			$current_id = $vorgaenger->vorgaenger_kalender_id;
+		}
+	}
+
 }
diff --git a/public/js/api/factory/tempus/kalender.js b/public/js/api/factory/tempus/kalender.js
index 61d555db6..ff5d6ff88 100644
--- a/public/js/api/factory/tempus/kalender.js
+++ b/public/js/api/factory/tempus/kalender.js
@@ -8,6 +8,46 @@ export default {
 			params: { ...filter, start_date, end_date }
 		};
 	},
+	getPlanLecturer(start_date, end_date)
+	{
+		return {
+			method: 'get',
+			url: '/api/frontend/v1/tempus/Kalender/getPlanLecturer',
+			params: { start_date, end_date }
+		};
+	},
+	getPlanStudent(start_date, end_date)
+	{
+		return {
+			method: 'get',
+			url: '/api/frontend/v1/tempus/Kalender/getPlanStudent',
+			params: { start_date, end_date }
+		};
+	},
+
+	syncToLecturer(kalender_id)
+	{
+		return {
+			method: 'post',
+			url: '/api/frontend/v1/tempus/Kalender/syncToLecturer',
+			params: { kalender_id }
+		};
+	},
+	syncToStudent(kalender_id)
+	{
+		return {
+			method: 'post',
+			url: '/api/frontend/v1/tempus/Kalender/syncToStudent',
+			params: { kalender_id }
+		};
+	},
+	sync()
+	{
+		return {
+			method: 'post',
+			url: '/api/frontend/v1/tempus/Kalender/sync',
+		};
+	},
 	getLektorZeitsperren(emp, start_date, end_date) {
 		return {
 			method: 'get',
@@ -50,4 +90,19 @@ export default {
 		};
 	},
 
+	getHistory(kalender_id) {
+		return {
+			method: 'get',
+			url: '/api/frontend/v1/tempus/Kalender/getHistory',
+			params: { kalender_id }
+		};
+	},
+	deleteEntry(kalender_id) {
+		return {
+			method: 'post',
+			url: '/api/frontend/v1/tempus/Kalender/deleteEntry',
+			params: { kalender_id }
+		};
+	},
+
 };
diff --git a/public/js/components/Calendar/Base/Grid/Line/Event.js b/public/js/components/Calendar/Base/Grid/Line/Event.js
index 2ee172e76..9ed4d80df 100644
--- a/public/js/components/Calendar/Base/Grid/Line/Event.js
+++ b/public/js/components/Calendar/Base/Grid/Line/Event.js
@@ -86,7 +86,6 @@ export default {
 			});
 		},
 		onRightClick(evt) {
-
 			this.contextMenu.show = true;
 			this.contextMenu.x = evt.clientX;
 			this.contextMenu.y = evt.clientY;
diff --git a/public/js/components/Tempus/Tempus.js b/public/js/components/Tempus/Tempus.js
index afd37c846..a9e2612b5 100644
--- a/public/js/components/Tempus/Tempus.js
+++ b/public/js/components/Tempus/Tempus.js
@@ -148,6 +148,8 @@ export default {
 			visibleStatus: ['all'],
 			selectedStudiensemester: this.studiensemester_kurzbz ?? this.defaultSemester,
 			calendarDate: luxon.DateTime.now().setZone(this.config.timezone).toISODate(),
+			historyEntries: [],
+			previewRole: 'planer'
 		}
 	},
 	computed: {
@@ -158,7 +160,27 @@ export default {
 						label: 'Raumauswahl',
 						icon: 'fa-solid fa-door-open',
 						action: this.openRaumauswahl
-					}
+					},
+					{
+						label: 'Sync to Lektor',
+						icon: 'fa-solid fa-chalkboard-user',
+						action: (orig) => this.$api.call(ApiKalender.syncToLecturer(orig.kalender_id)).then(() => this.$refs.calendar.resetEventLoader())
+					},
+					{
+						label: 'Sync to Student',
+						icon: 'fa-solid fa-user-graduate',
+						action: (orig) => this.$api.call(ApiKalender.syncToStudent(orig.kalender_id)).then(() => this.$refs.calendar.resetEventLoader())
+					},
+					{
+						label: 'History',
+						icon: 'fa-solid fa-clock-rotate-left',
+						action: this.openHistory
+					},
+					{
+						label: 'Delete',
+						icon: 'fa-solid fa-calendar-xmark',
+						action: this.deleteEntry
+					},
 				]
 			};
 		},
@@ -196,9 +218,29 @@ export default {
 
 				this.raumVorschlaege = result.data ?? [];
 				this.$refs.raumModal.show();
-
 			});
+		},
+		async deleteEntry(orig)
+		{
+			if (!orig?.kalender_id)
+				return;
 
+			await this.$api.call(ApiKalender.deleteEntry(
+				orig?.kalender_id
+			)).then(result => {
+				this.$refs.calendar.resetEventLoader();
+			});
+		},
+		async openHistory(orig)
+		{
+			if (!orig?.kalender_id)
+				return;
+			await this.$api.call(ApiKalender.getHistory(
+				orig.kalender_id
+			)).then(result => {
+				this.historyEntries = result.data ?? [];
+				this.$refs.historyModel.show();
+			});
 		},
 		async selectRaum(ort_kurzbz) {
 			const orig = this.raumModal;
@@ -308,6 +350,12 @@ export default {
 			if (hasLektoren)
 				filter.uid = this.lecturers.map(l => l.uid);
 
+			if (this.previewRole === 'lektor')
+				return [this.$api.call(ApiKalender.getPlanLecturer(start.toISODate(), end.toISODate()))];
+
+			if (this.previewRole === 'student')
+				return [this.$api.call(ApiKalender.getPlanStudent(start.toISODate(), end.toISODate()))];
+
 			return [this.$api.call(ApiKalender.getPlan(filter, start.toISODate(), end.toISODate()))];
 		},
 		toDateTime(value, timezone){
@@ -396,6 +444,8 @@ export default {
 		},
 
 		resizeHandler(payload) {
+			if (this.previewRole !== 'planer') //TODO (david) testzweck
+				return;
 			const { item, start, end } = payload;
 			const obj = item[0];
 			if (!obj?.orig?.kalender_id)
@@ -412,6 +462,8 @@ export default {
 		},
 
 		dropHandler(payload) {
+			if (this.previewRole !== 'planer') //TODO (david) testzweck
+				return;
 			const { item, start, end } = payload;
 			if (!item?.length)
 				return alert("Keine Daten gedroppt");
@@ -568,6 +620,10 @@ export default {
 			this.stg = null;
 			this.show_stg = null;
 			this.$refs.calendar.resetEventLoader();
+		},
+		triggerSync()
+		{
+			this.$api.call(ApiKalender.sync()).then(this.$refs.calendar.resetEventLoader())
 		}
 	},
 	watch: {
@@ -752,6 +808,36 @@ export default {
 							:show-toggle-all="false"
 							class="w-100"
 						/>
+						
+						<div class="d-flex gap-1 py-1">
+							<button
+								class="btn btn-sm"
+								:class="previewRole === 'planer' ? 'btn-dark' : 'btn-outline-dark'"
+								@click="previewRole = 'planer'; $refs.calendar.resetEventLoader()"
+							>
+								<i class="fa-solid fa-pen-ruler me-1"></i>Planer
+							</button>
+							<button
+								class="btn btn-sm"
+								:class="previewRole === 'lektor' ? 'btn-primary' : 'btn-outline-primary'"
+								@click="previewRole = 'lektor'; $refs.calendar.resetEventLoader()"
+							>
+								<i class="fa-solid fa-chalkboard-user me-1"></i>Lektor
+							</button>
+							<button
+								class="btn btn-sm"
+								:class="previewRole === 'student' ? 'btn-success' : 'btn-outline-success'"
+								@click="previewRole = 'student'; $refs.calendar.resetEventLoader()"
+							>
+								<i class="fa-solid fa-user-graduate me-1"></i>Student
+							</button>
+							<button
+								class="btn btn-sm btn-outline-danger"
+								@click="triggerSync"
+							>
+								<i class="fa-solid fa-rotate me-1"></i>Sync
+							</button>
+						</div>
 					</div>
 					<div class="room-selection" v-if="ort_kurzbz">
 						<div class="fw-semibold px-2 d-flex align-items-center justify-content-between">
@@ -846,5 +932,29 @@ export default {
 				<p v-else class="text-muted mb-0">Keine freien Räume gefunden.</p>
 			</template>
 		</bs-modal>
+		
+		<bs-modal ref="historyModel" class="bootstrap-prompt" dialogClass="modal-lg">
+			<template #title>History</template>
+			<template #default>
+				<table v-if="historyEntries.length" class="table table-bordered table-hover">
+					<thead class="table-light">
+						<tr>
+							<th>Von</th>
+							<th>Bis</th>
+							<th>Status</th>
+							<th>Ort</th>
+						</tr>
+					</thead>
+					<tbody>
+						<tr v-for="entry in historyEntries" :key="entry.id">
+							<td>{{ entry.von }}</td>
+							<td>{{ entry.bis }}</td>
+							<td>{{ entry.status_kurzbz }}</td>
+							<td>{{ entry.ort }}</td>
+						</tr>
+					</tbody>
+				</table>
+			</template>
+		</bs-modal>
 	</div>`
 };
\ No newline at end of file
diff --git a/system/dbupdate_3.4/46975_tempus.php b/system/dbupdate_3.4/46975_tempus.php
index 3b6f85355..975c61a03 100644
--- a/system/dbupdate_3.4/46975_tempus.php
+++ b/system/dbupdate_3.4/46975_tempus.php
@@ -78,12 +78,15 @@ if(!$result = @$db->db_query("SELECT kalender_id FROM lehre.tbl_kalender LIMIT 1
 	COMMENT ON TABLE lehre.tbl_kalender_status IS 'Calender visibility Status';
 
 	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'planning', E'planning', E'{\"In Planung\", \"Planning\"}', 1);
-	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'tosync', E'tosync', E'{\"Zu synchronisieren\", \"To sync\"}', 2);
-	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'todelete', E'todelete', E'{\"Zu löschen\", \"To delete\"}', 3);
-	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'visible_lektor', E'Sichtbar für Lektoren', E'{\"Sichtbar für Lektoren\", \"Visible for lecturers\"}', 4);
-	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'deleted', E'deleted', E'{\"Gelöscht\", \"Deleted\"}', 5);
-	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'archived', E'archived', E'{\"Archiviert\", \"Archived\"}', 6);
-	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'visible_student', E'Sichtbar für Studierende', E'{\"Sichtbar für Studierende\", \"Visible for students\"}', 7);
+	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'tosync_lektor', E'tosync_lektor', E'{\"Zu synchronisieren Lektoren\", \"To sync lecturers\"}', 2);
+	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'visible_lektor', E'Sichtbar für Lektoren', E'{\"Sichtbar für Lektoren\", \"Visible for lecturers\"}', 3);
+	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'tosync_student', E'tosync_lektor', E'{\"Zu synchronisieren Studierende\", \"To sync students\"}', 4);
+	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'visible_student', E'Sichtbar für Studierende', E'{\"Sichtbar für Studierende\", \"Visible for students\"}', 5);
+	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'todelete', E'todelete', E'{\"Zu löschen\", \"To delete\"}', 6);
+	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'deleted', E'deleted', E'{\"Gelöscht\", \"Deleted\"}', 7);
+	INSERT INTO lehre.tbl_kalender_status (status_kurzbz, bezeichnung, bezeichnung_mehrsprachig, sort) VALUES (E'archived', E'archived', E'{\"Archiviert\", \"Archived\"}', 8);
+
+	
 
 	ALTER TABLE lehre.tbl_kalender ADD CONSTRAINT tbl_kalender_status_fk FOREIGN KEY (status_kurzbz)
 	REFERENCES lehre.tbl_kalender_status (status_kurzbz) MATCH FULL