diff --git a/dav/common/calendar.fnk.php b/dav/common/calendar.fnk.php
index 11f31f7d..1245ee2e 100644
--- a/dav/common/calendar.fnk.php
+++ b/dav/common/calendar.fnk.php
@@ -1,5 +1,6 @@
 <?php
 
+use Friendica\Util\Temporal;
 
 define("DAV_ACL_READ", "{DAV:}read");
 define("DAV_ACL_WRITE", "{DAV:}write");
@@ -150,7 +151,7 @@ function vcard_source_compile($vcardsource)
  */
 function wdcal_php2MySqlTime($phpDate)
 {
-	return date("Y-m-d H:i:s", $phpDate);
+	return date(Temporal::MYSQL, $phpDate);
 }
 
 /**
@@ -159,7 +160,7 @@ function wdcal_php2MySqlTime($phpDate)
  */
 function wdcal_mySql2PhpTime($sqlDate)
 {
-	$ts = DateTime::createFromFormat("Y-m-d H:i:s", $sqlDate);
+	$ts = DateTime::createFromFormat(Temporal::MYSQL, $sqlDate);
 	return $ts->format("U");
 }
 
diff --git a/dav/common/calendar_rendering.fnk.php b/dav/common/calendar_rendering.fnk.php
index d80892f7..ae6e39dd 100644
--- a/dav/common/calendar_rendering.fnk.php
+++ b/dav/common/calendar_rendering.fnk.php
@@ -1,5 +1,6 @@
 <?php
 
+use Friendica\Util\Temporal;
 
 
 /**
@@ -109,15 +110,15 @@ function renderCalDavEntry_data(&$calendar, &$calendarobject)
 
 		q("INSERT INTO %s%sjqcalendar (`calendar_id`, `calendarobject_id`, `Summary`, `StartTime`, `EndTime`, `IsEditable`, `IsAllDayEvent`, `IsRecurring`, `Color`) VALUES
 			(%d, %d, '%s', CONVERT_TZ('%s', '$timezoneOffset', @@session.time_zone), CONVERT_TZ('%s', '$timezoneOffset', @@session.time_zone), %d, %d, %d, '%s')",
-			CALDAV_SQL_DB, CALDAV_SQL_PREFIX, IntVal($calendar["id"]), IntVal($calendarobject["id"]), dbesc($event["summary"]), date("Y-m-d H:i:s", $start),
-			date("Y-m-d H:i:s", $last_end), 1, $allday, $recurring, dbesc(substr($event["color"], 1))
+			CALDAV_SQL_DB, CALDAV_SQL_PREFIX, IntVal($calendar["id"]), IntVal($calendarobject["id"]), dbesc($event["summary"]), date(Temporal::MYSQL, $start),
+			date(Temporal::MYSQL, $last_end), 1, $allday, $recurring, dbesc(substr($event["color"], 1))
 		);
 
 		foreach ($alarms as $alarm) {
 			$alarm    = renderCalDavEntry_calcalarm($alarm, $component);
 			$notified = ($alarm->getTimestamp() < time() ? 1 : 0);
 			q("INSERT INTO %s%snotifications (`calendar_id`, `calendarobject_id`, `alert_date`, `notified`) VALUES (%d, %d, CONVERT_TZ('%s', '$timezoneOffset', @@session.time_zone), %d)",
-				CALDAV_SQL_DB, CALDAV_SQL_PREFIX, IntVal($calendar["id"]), IntVal($calendarobject["id"]), $alarm->format("Y-m-d H:i:s"), $notified
+				CALDAV_SQL_DB, CALDAV_SQL_PREFIX, IntVal($calendar["id"]), IntVal($calendarobject["id"]), $alarm->format(Temporal::MYSQL), $notified
 			);
 		}
 
diff --git a/dav/common/wdcal_backend.inc.php b/dav/common/wdcal_backend.inc.php
index a3e18eb3..5418c90a 100644
--- a/dav/common/wdcal_backend.inc.php
+++ b/dav/common/wdcal_backend.inc.php
@@ -1,6 +1,7 @@
 <?php
 
 use Friendica\Core\L10n;
+use Friendica\Util\Temporal;
 
 /**
  * @param mixed $obj
@@ -100,9 +101,9 @@ function wdcal_print_feed($base_path = "")
 				else $type = Sabre\VObject\Property\DateTime::LOCALTZ;
 
 				$datetime_start = new Sabre\VObject\Property\DateTime("DTSTART");
-				$datetime_start->setDateTime(new DateTime(date("Y-m-d H:i:s", IntVal($_REQUEST["CalendarStartTime"]))), $type);
+				$datetime_start->setDateTime(new DateTime(date(Temporal::MYSQL, IntVal($_REQUEST["CalendarStartTime"]))), $type);
 				$datetime_end = new Sabre\VObject\Property\DateTime("DTEND");
-				$datetime_end->setDateTime(new DateTime(date("Y-m-d H:i:s", IntVal($_REQUEST["CalendarEndTime"]))), $type);
+				$datetime_end->setDateTime(new DateTime(date(Temporal::MYSQL, IntVal($_REQUEST["CalendarEndTime"]))), $type);
 
 				$component->add($datetime_start);
 				$component->add($datetime_end);
@@ -182,9 +183,9 @@ function wdcal_print_feed($base_path = "")
 				else $type = Sabre\VObject\Property\DateTime::LOCALTZ;
 
 				$datetime_start = new Sabre\VObject\Property\DateTime("DTSTART");
-				$datetime_start->setDateTime(new DateTime(date("Y-m-d H:i:s", IntVal($_REQUEST["CalendarStartTime"]))), $type);
+				$datetime_start->setDateTime(new DateTime(date(Temporal::MYSQL, IntVal($_REQUEST["CalendarStartTime"]))), $type);
 				$datetime_end = new Sabre\VObject\Property\DateTime("DTEND");
-				$datetime_end->setDateTime(new DateTime(date("Y-m-d H:i:s", IntVal($_REQUEST["CalendarEndTime"]))), $type);
+				$datetime_end->setDateTime(new DateTime(date(Temporal::MYSQL, IntVal($_REQUEST["CalendarEndTime"]))), $type);
 
 				$component->__unset("DTSTART");
 				$component->__unset("DTEND");
diff --git a/dav/common/wdcal_edit.inc.php b/dav/common/wdcal_edit.inc.php
index f4ac90c9..8154a68b 100644
--- a/dav/common/wdcal_edit.inc.php
+++ b/dav/common/wdcal_edit.inc.php
@@ -1,6 +1,7 @@
 <?php
 
 use Friendica\Core\L10n;
+use Friendica\Util\Temporal;
 
 /**
  * @param wdcal_local $localization
@@ -520,9 +521,9 @@ function wdcal_set_component_date(&$component, &$localization)
 		$type     = Sabre\VObject\Property\DateTime::LOCALTZ;
 	}
 	$datetime_start = new Sabre\VObject\Property\DateTime("DTSTART");
-	$datetime_start->setDateTime(new DateTime(date("Y-m-d H:i:s", $ts_start)), $type);
+	$datetime_start->setDateTime(new DateTime(date(Temporal::MYSQL, $ts_start)), $type);
 	$datetime_end = new Sabre\VObject\Property\DateTime("DTEND");
-	$datetime_end->setDateTime(new DateTime(date("Y-m-d H:i:s", $ts_end)), $type);
+	$datetime_end->setDateTime(new DateTime(date(Temporal::MYSQL, $ts_end)), $type);
 
 	$component->__unset("DTSTART");
 	$component->__unset("DTEND");
@@ -598,7 +599,7 @@ function wdcal_set_component_recurrence(&$component, &$localization)
 			$date           = $localization->date_local2timestamp($_REQUEST["rec_until_date"]);
 			$part_until     = ";UNTIL=" . date("Ymd", $date);
 			$datetime_until = new Sabre\VObject\Property\DateTime("UNTIL");
-			$datetime_until->setDateTime(new DateTime(date("Y-m-d H:i:s", $date)), Sabre\VObject\Property\DateTime::DATE);
+			$datetime_until->setDateTime(new DateTime(date(Temporal::MYSQL, $date)), Sabre\VObject\Property\DateTime::DATE);
 			break;
 		case "count":
 			$part_until = ";COUNT=" . IntVal($_REQUEST["rec_until_count"]);
@@ -645,7 +646,7 @@ function wdcal_set_component_recurrence(&$component, &$localization)
 	if (isset($_REQUEST["rec_exceptions"])) {
 		$arr = array();
 		foreach ($_REQUEST["rec_exceptions"] as $except) {
-			$arr[] = new DateTime(date("Y-m-d H:i:s", $except));
+			$arr[] = new DateTime(date(Temporal::MYSQL, $except));
 		}
 		/** @var Sabre\VObject\Property\MultiDateTime $prop */
 		$prop = Sabre\VObject\Property::create("EXDATE");
diff --git a/dav/friendica/dav_caldav_backend_virtual_friendica.inc.php b/dav/friendica/dav_caldav_backend_virtual_friendica.inc.php
index 405bbb19..3baaa10c 100644
--- a/dav/friendica/dav_caldav_backend_virtual_friendica.inc.php
+++ b/dav/friendica/dav_caldav_backend_virtual_friendica.inc.php
@@ -88,9 +88,9 @@ class Sabre_CalDAV_Backend_Friendica extends Sabre_CalDAV_Backend_Virtual
 			$type           = ($allday ? Sabre\VObject\Property\DateTime::DATE : Sabre\VObject\Property\DateTime::LOCALTZ);
 
 			$datetime_start = new Sabre\VObject\Property\DateTime("DTSTART");
-			$datetime_start->setDateTime(new DateTime(date("Y-m-d H:i:s", $ts_start)), $type);
+			$datetime_start->setDateTime(new DateTime(date(Temporal::MYSQL, $ts_start)), $type);
 			$datetime_end = new Sabre\VObject\Property\DateTime("DTEND");
-			$datetime_end->setDateTime(new DateTime(date("Y-m-d H:i:s", $ts_end)), $type);
+			$datetime_end->setDateTime(new DateTime(date(Temporal::MYSQL, $ts_end)), $type);
 
 			$component->add($datetime_start);
 			$component->add($datetime_end);
@@ -175,11 +175,11 @@ class Sabre_CalDAV_Backend_Friendica extends Sabre_CalDAV_Backend_Virtual
 		}
 
 		if ($date_from != "") {
-			if (is_numeric($date_from)) $sql_where .= " AND `finish` >= '" . date("Y-m-d H:i:s", $date_from) . "'";
+			if (is_numeric($date_from)) $sql_where .= " AND `finish` >= '" . date(Temporal::MYSQL, $date_from) . "'";
 			else $sql_where .= " AND `finish` >= '" . dbesc($date_from) . "'";
 		}
 		if ($date_to != "") {
-			if (is_numeric($date_to)) $sql_where .= " AND `start` <= '" . date("Y-m-d H:i:s", $date_to) . "'";
+			if (is_numeric($date_to)) $sql_where .= " AND `start` <= '" . date(Temporal::MYSQL, $date_to) . "'";
 			else $sql_where .= " AND `start` <= '" . dbesc($date_to) . "'";
 		}
 		$ret = [];
diff --git a/pumpio/pumpio.php b/pumpio/pumpio.php
index bdc56795..7e34eab3 100644
--- a/pumpio/pumpio.php
+++ b/pumpio/pumpio.php
@@ -672,7 +672,7 @@ function pumpio_sync(&$a) {
 	if ($abandon_days < 1)
 		$abandon_days = 0;
 
-	$abandon_limit = date("Y-m-d H:i:s", time() - $abandon_days * 86400);
+	$abandon_limit = date(Temporal::MYSQL, time() - $abandon_days * 86400);
 
 	$r = q("SELECT * FROM `pconfig` WHERE `cat` = 'pumpio' AND `k` = 'import' AND `v` = '1' ORDER BY RAND() ");
 	if(count($r)) {
diff --git a/statusnet/statusnet.php b/statusnet/statusnet.php
index 57095412..c5b62a5d 100644
--- a/statusnet/statusnet.php
+++ b/statusnet/statusnet.php
@@ -760,7 +760,7 @@ function statusnet_cron(App $a, $b)
 		$abandon_days = 0;
 	}
 
-	$abandon_limit = date("Y-m-d H:i:s", time() - $abandon_days * 86400);
+	$abandon_limit = date(Temporal::MYSQL, time() - $abandon_days * 86400);
 
 	$r = q("SELECT * FROM `pconfig` WHERE `cat` = 'statusnet' AND `k` = 'import' AND `v` ORDER BY RAND()");
 	if (count($r)) {
diff --git a/twitter/twitter.php b/twitter/twitter.php
index d6d0ba7b..9c2804b1 100644
--- a/twitter/twitter.php
+++ b/twitter/twitter.php
@@ -682,7 +682,7 @@ function twitter_cron(App $a, $b)
 		$abandon_days = 0;
 	}
 
-	$abandon_limit = date("Y-m-d H:i:s", time() - $abandon_days * 86400);
+	$abandon_limit = date(Temporal::MYSQL, time() - $abandon_days * 86400);
 
 	$r = q("SELECT * FROM `pconfig` WHERE `cat` = 'twitter' AND `k` = 'import' AND `v` = '1'");
 	if (count($r)) {