diff --git a/calendar/inc/class.calendar_boupdate.inc.php b/calendar/inc/class.calendar_boupdate.inc.php
index 6b840ea2e3..f8d761636c 100644
--- a/calendar/inc/class.calendar_boupdate.inc.php
+++ b/calendar/inc/class.calendar_boupdate.inc.php
@@ -245,9 +245,6 @@ class calendar_boupdate extends calendar_bo
 			return $conflicts;
 		}
 
-		// See if we need to reset any participant statuses
-		$this->check_reset_stati($event, $old_event);
-
 		//echo "saving $event[id]="; _debug_array($event);
 		$event2save = $event;
 
@@ -2920,60 +2917,4 @@ class calendar_boupdate extends calendar_bo
 			$this->so->purge(time() - 365*24*3600*(float)$age);
 		}
 	}
-
-	/**
-	 * Check to see if we need to reset the status of any of the participants
-	 * - Current user is never reset
-	 * - Other users we respect their preference
-	 * - Non-users status is always reset
-	 *
-	 * @param Array $event New event
-	 * @param Array $old_event Event before modification
-	 *
-	 * @return boolean true if any statuses were reset
-	 */
-	protected function check_reset_stati(&$event, $old_event)
-	{
-		if(!$old_event || !is_array($old_event))
-		{
-			return false;
-		}
-
-		$status_reset = false;
-		$sameday = (date('Ymd', $old_event['start']) == date('Ymd', $event['start']));
-		foreach((array)$event['participants'] as $uid => $status)
-		{
-			$q = $r = null;
-			calendar_so::split_status($status,$q,$r);
-			if($uid == $this->user || $status == 'U')
-			{
-				continue;
-			}
-
-			// Just user accounts
-			if (is_int($uid))
-			{
-				$preferences = new Api\Preferences($uid);
-				$part_prefs = $preferences->read_repository();
-				switch ($part_prefs['calendar']['reset_stati'])
-				{
-					case 'no':
-						break;
-					case 'startday':
-						if ($sameday) break;
-					default:
-						$status_reset = true;
-						$event['participants'][$uid] = calendar_so::combine_status('U',$q,$r);
-				}
-			}
-			// All other participant types
-			else
-			{
-				$status_reset = true;
-				$event['participants'][$uid] = calendar_so::combine_status('U',$q,$r);
-			}
-		}
-		return $status_reset;
-
-	}
 }
diff --git a/calendar/inc/class.calendar_uiforms.inc.php b/calendar/inc/class.calendar_uiforms.inc.php
index b9d28f4093..92ffb0d50f 100644
--- a/calendar/inc/class.calendar_uiforms.inc.php
+++ b/calendar/inc/class.calendar_uiforms.inc.php
@@ -852,6 +852,28 @@ class calendar_uiforms extends calendar_ui
 							$old_event['end'] != $event['end'] ||
 							$event['whole_day'] != $old_event['whole_day'])
 						{
+							$sameday = (date('Ymd', $old_event['start']) == date('Ymd', $event['start']));
+							foreach((array)$event['participants'] as $uid => $status)
+							{
+								$q = $r = null;
+								calendar_so::split_status($status,$q,$r);
+								if ($uid[0] != 'c' && $uid[0] != 'e' && $uid != $this->bo->user && $status != 'U')
+								{
+									$preferences = new Api\Preferences($uid);
+									$part_prefs = $preferences->read_repository();
+									switch ($part_prefs['calendar']['reset_stati'])
+									{
+										case 'no':
+											break;
+										case 'startday':
+											if ($sameday) break;
+										default:
+											$status_reset_to_unknown = true;
+											$event['participants'][$uid] = calendar_so::combine_status('U',$q,$r);
+											// todo: report reset status to user
+									}
+								}
+							}
 							// check if we need to move the alarms, because they are relative
 							$this->bo->check_move_alarms($event, $old_event);
 						}
@@ -3041,6 +3063,27 @@ class calendar_uiforms extends calendar_ui
 
 		$status_reset_to_unknown = false;
 		$sameday = (date('Ymd', $old_event['start']) == date('Ymd', $event['start']));
+		foreach((array)$event['participants'] as $uid => $status)
+		{
+			$q = $r = null;
+			calendar_so::split_status($status,$q,$r);
+			if ($uid[0] != 'c' && $uid[0] != 'e' && $uid != $this->bo->user && $status != 'U')
+			{
+				$preferences = new Api\Preferences($uid);
+				$part_prefs = $preferences->read_repository();
+				switch ($part_prefs['calendar']['reset_stati'])
+				{
+					case 'no':
+						break;
+					case 'startday':
+						if ($sameday) break;
+					default:
+						$status_reset_to_unknown = true;
+						$event['participants'][$uid] = calendar_so::combine_status('U',$q,$r);
+						// todo: report reset status to user
+				}
+			}
+		}
 
 		$message = false;
 		$conflicts=$this->bo->update($event,$ignore_conflicts, true, false, true, $message);
diff --git a/calendar/tests/ResetParticipantStatusTest.php b/calendar/tests/ResetParticipantStatusTest.php
deleted file mode 100644
index c67b4674d5..0000000000
--- a/calendar/tests/ResetParticipantStatusTest.php
+++ /dev/null
@@ -1,283 +0,0 @@
-<?php
-
-/**
- * Tests for resetting participant status if the event changes
- *
- * @link http://www.egroupware.org
- * @author Nathan Gray
- * @package calendar
- * @copyright (c) 2019  Nathan Gray
- * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
- */
-
-namespace EGroupware\calendar;
-
-require_once realpath(__DIR__.'/../../api/tests/AppTest.php');	// Application test base
-
-use Egroupware\Api;
-
-class ResetParticipantStatusTest extends \EGroupware\Api\AppTest
-{
-	// Another user we can use for testing
-	protected $account_id;
-
-	// Method under test with modified access
-	private $check_method = null;
-
-	public static function setUpBeforeClass()
-	{
-		parent::setUpBeforeClass();
-
-	}
-	public static function tearDownAfterClass()
-	{
-		parent::tearDownAfterClass();
-	}
-
-	public function setUp()
-	{
-		$this->bo = new \calendar_boupdate();
-
-		// Add another user
-		$this->account_id = $this->make_test_user();
-
-		// Make check_reset_status method accessable
-		$class = new \ReflectionClass($this->bo);
-        $this->check_method = $class->getMethod('check_reset_stati');
-        $this->check_method->setAccessible(true);
-	}
-
-	public function tearDown()
-	{
-
-		// Clean up user
-		$GLOBALS['egw']->accounts->delete($this->account_id);
-	}
-
-	/**
-	 * Test that various participant strings are not changed if nothing changes
-	 *
-	 * @param array $participant Participant to test
-	 *
-	 * @dataProvider participantProvider
-	 */
-	public function testNoChange($participant)
-	{
-		$this->fix_id($participant);
-
-		// Get test event
-		$event = $old_event = $this->get_event();
-
-		// No change
-		$event['participant'] = $old_event['participant'] = $participant;
-
-		// Check & reset status
-        $reset = $this->check_method->invokeArgs($this->bo, array(&$event, $old_event));
-
-		// Verify
-		$this->assertFalse($reset);
-	}
-
-
-	/**
-	 * Test that moving the event forward 1 hour works correctly.
-	 * - For current user, no change to status
-	 * - For other users, respect the preference
-	 * - For non-users, always reset status.
-	 *
-	 * @param type $participant
-	 *
-	 * @dataProvider participantProvider
-	 */
-	public function testForwardOneHour($participant)
-	{
-		$this->fix_id($participant);
-		$participant[$this->account_id] = 'A';
-
-		// Get test event
-		$event = $old_event = $this->get_event();
-		$event['participants'] = $old_event['participants'] = $participant;
-
-		// Forward 1 hour
-		$event['start'] += 3600;
-		$event['end'] += 3600;
-
-		// Set preference to only if start day changes, so no reset is done
-		$pref = array(
-			'account' => $this->account_id,
-			'pref' => 'user',
-			'app' => 'calendar',
-			'set' => array('reset_stati' => 'startday')
-		);
-		$pref_command = new \admin_cmd_edit_preferences($pref);
-		$pref_command->run();
-
-
-		// Check & reset status
-        $reset = $this->check_method->invokeArgs($this->bo, array(&$event, $old_event));
-
-		// Verify change as expected
-		foreach($event['participants'] as $id => $status)
-		{
-			if($id == $this->bo->user)
-			{
-				// Current user, no change
-				$this->assertEquals($participant[$id], $status, "Participant $id was changed");
-			}
-			if(is_int($id))
-			{
-				// Users respect preference, in this case no change
-				$this->assertEquals($participant[$id], $status, "Participant $id was changed");
-			}
-			else
-			{
-				// Non-user gets reset
-				$this->assertEquals('U', $status[0], "Participant $id did not get reset");
-			}
-		}
-	}
-
-	/**
-	 * Test that moving the event to a different day resets or keeps status for
-	 * user accounts according to that account's preference
-	 *
-	 * @param Array $change_preference One of the allowed preference values
-	 *
-	 * @dataProvider statiPreferenceProvider
-	 */
-	public function testChangeUsesPreference($change_preference)
-	{
-		// Get test event
-		$event = $old_event = $this->get_event();
-		$participant = $event['participants'] = $old_event['participants'] = array(
-			// Current user is never changed
-			$this->bo->user => 'A',
-			// Other user will use preference
-			$this->account_id => 'A'
-		);
-
-		// Set preference
-		$pref = array(
-			'account' => $this->account_id,
-			'pref' => 'user',
-			'app' => 'calendar',
-			'set' => array('reset_stati' => $change_preference)
-		);
-		$pref_command = new \admin_cmd_edit_preferences($pref);
-		$pref_command->run();
-
-		// Forward 1 day
-		$event['start'] += 24*3600;
-		$event['end'] += 24*3600;
-
-		// Check & reset status
-        $reset = $this->check_method->invokeArgs($this->bo, array(&$event, $old_event));
-
-		// Verify no change in current user
-		$this->assertEquals($participant[$this->bo->user], $event['participants'][$this->bo->user]);
-
-		// Other user may change though
-		switch($pref)
-		{
-			case 'no':
-				$this->assertFalse($reset);
-				$this->assertEquals($participant[$this->account_id], $event['participants'][$this->account_id]);
-				break;
-			case 'all':
-			case 'sameday':
-				$this->assertTrue($reset);
-				$this->assertEquals('U', $event['participants'][$this->account_id][0]);
-				break;
-		}
-	}
-
-	protected function get_event()
-	{
-		return array(
-			'title' => 'Test event for ' . $this->getName(),
-			'owner' => $GLOBALS['egw_info']['user']['account_id'],
-			'start' => 1602324600,
-			'end'   => 1602328200
-		);
-	}
-
-	protected function make_test_user()
-	{
-		$account = array(
-			'account_lid' => 'user_test',
-			'account_firstname' => 'Test',
-			'account_lastname' => 'Test'
-		);
-		$command = new \admin_cmd_edit_user(false, $account);
-		$command->comment = 'Needed for unit test ' . $this->getName();
-		$command->run();
-		return $command->account;
-	}
-
-	/**
-	 * Account ID is unknown when participantProvider is run, so we swap in
-	 * the ID
-	 *
-	 * @param Array $participants
-	 */
-	protected function fix_id(&$participants)
-	{
-		// Provider didn't know test user's ID, so swap it in
-		foreach($participants as $id => $status)
-		{
-			if($id == $GLOBALS['egw_info']['user']['account_lid'])
-			{
-				unset($participants[$id]);
-				$participants[$GLOBALS['egw_info']['user']['account_id']] = $status;
-			}
-		}
-	}
-
-	/**
-	 * Different values for the status change on event change preference
-	 * 
-	 * @see calendar_hooks::settings()
-	 */
-	public function statiPreferenceProvider()
-	{
-		return array(
-			array('no'), // Never change status
-			array('all'),// Always change status
-			array('startday') // Change status of start date changes
-		);
-	}
-
-	public function participantProvider()
-	{
-		return array(
-			// Participant ID => status
-
-			// User - 'demo' will get changed for real ID later
-			array(array('demo' => 'A')),
-			array(array('demo' => 'R')),
-			array(array('demo' => 'T')),
-			array(array('demo' => 'U')),
-			array(array('demo' => 'D')),
-
-			// These don't have to be real IDs since we're not actually doing
-			// anything with the entry itself, just checking its type
-
-			// Contact
-			array(array('c1' => 'A')),
-			array(array('c1' => 'R')),
-			array(array('c1' => 'T')),
-			array(array('c1' => 'U')),
-			array(array('c1' => 'D')),
-
-			// Resource
-			array(array('r1' => 'A')),
-			array(array('r1' => 'R')),
-			array(array('r1' => 'T')),
-			array(array('r1' => 'U')),
-			array(array('r1' => 'D')),
-
-			// All together, just for fun
-			array(array('demo' => 'A', 'c1' => 'D', 'r1' => 'T'))
-		);
-	}
-}
\ No newline at end of file