diff --git a/lib/private/Calendar/Manager.php b/lib/private/Calendar/Manager.php
index 1bcea5d73533f..adfae6e85ac9f 100644
--- a/lib/private/Calendar/Manager.php
+++ b/lib/private/Calendar/Manager.php
@@ -261,8 +261,13 @@ public function handleIMip(
 		}
 
 		if (!isset($vEvent->ORGANIZER)) {
-			$this->logger->warning('iMip message event dose not contains an organizer');
-			return false;
+			// quirks mode: for Microsoft Exchange Servers use recipient as organizer if no organizer is set
+			if (isset($options['recipient']) && $options['recipient'] !== '') {
+				$vEvent->add('ORGANIZER', 'mailto:' . $options['recipient']);
+			} else {
+				$this->logger->warning('iMip message event does not contain an organizer and no recipient was provided');
+				return false;
+			}
 		}
 
 		if (!isset($vEvent->ATTENDEE)) {
@@ -335,7 +340,8 @@ public function handleIMipRequest(
 			return false;
 		}
 		$userId = substr($principalUri, 17);
-		return $this->handleIMip($userId, $calendarData);
+		$options = ['recipient' => $recipient];
+		return $this->handleIMip($userId, $calendarData, $options);
 	}
 
 	/**
@@ -354,7 +360,8 @@ public function handleIMipReply(
 			return false;
 		}
 		$userId = substr($principalUri, 17);
-		return $this->handleIMip($userId, $calendarData);
+		$options = ['recipient' => $recipient];
+		return $this->handleIMip($userId, $calendarData, $options);
 	}
 
 	/**
@@ -374,7 +381,8 @@ public function handleIMipCancel(
 			return false;
 		}
 		$userId = substr($principalUri, 17);
-		return $this->handleIMip($userId, $calendarData);
+		$options = ['recipient' => $recipient];
+		return $this->handleIMip($userId, $calendarData, $options);
 	}
 
 	public function createEventBuilder(): ICalendarEventBuilder {
diff --git a/lib/public/Calendar/IManager.php b/lib/public/Calendar/IManager.php
index ae3284256af09..fa108192be083 100644
--- a/lib/public/Calendar/IManager.php
+++ b/lib/public/Calendar/IManager.php
@@ -143,7 +143,7 @@ public function newQuery(string $principalUri) : ICalendarQuery;
 	/**
 	 * Handles a iMip message
 	 *
-	 * @param array{absent?: "create"} $options
+	 * @param array{absent?: "create", recipient?: string} $options
 	 *
 	 * @throws \OCP\DB\Exception
 	 *
diff --git a/tests/lib/Calendar/ManagerTest.php b/tests/lib/Calendar/ManagerTest.php
index 2e7217e06c814..d343745022643 100644
--- a/tests/lib/Calendar/ManagerTest.php
+++ b/tests/lib/Calendar/ManagerTest.php
@@ -387,6 +387,82 @@ public function testHandleImipWithNoEvent(): void {
 		$this->assertFalse($result);
 	}
 
+	public function testHandleImipMissingOrganizerWithRecipient(): void {
+		// construct mock user calendar
+		$userCalendar = $this->createMock(ITestCalendar::class);
+		$userCalendar->expects(self::once())
+			->method('isDeleted')
+			->willReturn(false);
+		$userCalendar->expects(self::once())
+			->method('isWritable')
+			->willReturn(true);
+		$userCalendar->expects(self::once())
+			->method('search')
+			->willReturn([['uri' => 'principals/user/attendee1/personal']]);
+		// construct mock calendar manager and returns
+		/** @var Manager&MockObject $manager */
+		$manager = $this->getMockBuilder(Manager::class)
+			->setConstructorArgs([
+				$this->coordinator,
+				$this->container,
+				$this->logger,
+				$this->time,
+				$this->secureRandom,
+				$this->userManager,
+				$this->serverFactory,
+				$this->propertyMapper,
+			])
+			->onlyMethods(['getCalendarsForPrincipal'])
+			->getMock();
+		$manager->expects(self::once())
+			->method('getCalendarsForPrincipal')
+			->willReturn([$userCalendar]);
+		// construct parameters
+		$userId = 'attendee1';
+		$calendar = $this->vCalendar1a;
+		$calendar->add('METHOD', 'REQUEST');
+		$calendar->VEVENT->remove('ORGANIZER');
+		// construct user calendar returns
+		$userCalendar->expects(self::once())
+			->method('handleIMipMessage');
+		// test method
+		$result = $manager->handleIMip($userId, $calendar->serialize(), ['recipient' => 'organizer@testing.com']);
+	}
+
+	public function testHandleImipMissingOrganizerNoRecipient(): void {
+		// construct mock user calendar
+		$userCalendar = $this->createMock(ITestCalendar::class);
+		// construct mock calendar manager and returns
+		/** @var Manager&MockObject $manager */
+		$manager = $this->getMockBuilder(Manager::class)
+			->setConstructorArgs([
+				$this->coordinator,
+				$this->container,
+				$this->logger,
+				$this->time,
+				$this->secureRandom,
+				$this->userManager,
+				$this->serverFactory,
+				$this->propertyMapper,
+			])
+			->onlyMethods(['getCalendarsForPrincipal'])
+			->getMock();
+		$manager->expects(self::once())
+			->method('getCalendarsForPrincipal')
+			->willReturn([$userCalendar]);
+		// construct parameters
+		$userId = 'attendee1';
+		$calendar = $this->vCalendar1a;
+		$calendar->add('METHOD', 'REQUEST');
+		$calendar->VEVENT->remove('ORGANIZER');
+		// Logger expects warning
+		$this->logger->expects($this->once())
+			->method('warning')
+			->with('iMip message event does not contain an organizer and no recipient was provided');
+
+		$result = $manager->handleIMip($userId, $calendar->serialize(), []);
+	}
+
 	public function testHandleImipWithNoUid(): void {
 		// construct mock user calendar
 		$userCalendar = $this->createMock(ITestCalendar::class);