diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index ff6ac0a0928c9..37aea6b228326 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -108,6 +108,7 @@
     'OCA\\DAV\\CalDAV\\Sharing\\Service' => $baseDir . '/../lib/CalDAV/Sharing/Service.php',
     'OCA\\DAV\\CalDAV\\Status\\StatusService' => $baseDir . '/../lib/CalDAV/Status/StatusService.php',
     'OCA\\DAV\\CalDAV\\TimezoneService' => $baseDir . '/../lib/CalDAV/TimezoneService.php',
+    'OCA\\DAV\\CalDAV\\TipBroker' => $baseDir . '/../lib/CalDAV/TipBroker.php',
     'OCA\\DAV\\CalDAV\\Trashbin\\DeletedCalendarObject' => $baseDir . '/../lib/CalDAV/Trashbin/DeletedCalendarObject.php',
     'OCA\\DAV\\CalDAV\\Trashbin\\DeletedCalendarObjectsCollection' => $baseDir . '/../lib/CalDAV/Trashbin/DeletedCalendarObjectsCollection.php',
     'OCA\\DAV\\CalDAV\\Trashbin\\Plugin' => $baseDir . '/../lib/CalDAV/Trashbin/Plugin.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index 00d90a532fb0d..9e1290c86cf33 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -123,6 +123,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\CalDAV\\Sharing\\Service' => __DIR__ . '/..' . '/../lib/CalDAV/Sharing/Service.php',
         'OCA\\DAV\\CalDAV\\Status\\StatusService' => __DIR__ . '/..' . '/../lib/CalDAV/Status/StatusService.php',
         'OCA\\DAV\\CalDAV\\TimezoneService' => __DIR__ . '/..' . '/../lib/CalDAV/TimezoneService.php',
+        'OCA\\DAV\\CalDAV\\TipBroker' => __DIR__ . '/..' . '/../lib/CalDAV/TipBroker.php',
         'OCA\\DAV\\CalDAV\\Trashbin\\DeletedCalendarObject' => __DIR__ . '/..' . '/../lib/CalDAV/Trashbin/DeletedCalendarObject.php',
         'OCA\\DAV\\CalDAV\\Trashbin\\DeletedCalendarObjectsCollection' => __DIR__ . '/..' . '/../lib/CalDAV/Trashbin/DeletedCalendarObjectsCollection.php',
         'OCA\\DAV\\CalDAV\\Trashbin\\Plugin' => __DIR__ . '/..' . '/../lib/CalDAV/Trashbin/Plugin.php',
diff --git a/apps/dav/lib/CalDAV/Schedule/Plugin.php b/apps/dav/lib/CalDAV/Schedule/Plugin.php
index 51aa46464876d..971f4b9cafd96 100644
--- a/apps/dav/lib/CalDAV/Schedule/Plugin.php
+++ b/apps/dav/lib/CalDAV/Schedule/Plugin.php
@@ -34,6 +34,7 @@
 use OCA\DAV\CalDAV\Calendar;
 use OCA\DAV\CalDAV\CalendarHome;
 use OCA\DAV\CalDAV\DefaultCalendarValidator;
+use OCA\DAV\CalDAV\TipBroker;
 use OCP\IConfig;
 use Psr\Log\LoggerInterface;
 use Sabre\CalDAV\ICalendar;
@@ -108,6 +109,13 @@ public function initialize(Server $server) {
 		);
 	}
 
+	/**
+	 * Returns an instance of the iTip\Broker.
+	 */
+	protected function createITipBroker(): TipBroker {
+		return new TipBroker();
+	}
+
 	/**
 	 * Allow manual setting of the object change URL
 	 * to support public write
diff --git a/apps/dav/lib/CalDAV/TipBroker.php b/apps/dav/lib/CalDAV/TipBroker.php
new file mode 100644
index 0000000000000..43eff124f0bb1
--- /dev/null
+++ b/apps/dav/lib/CalDAV/TipBroker.php
@@ -0,0 +1,187 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\DAV\CalDAV;
+
+use Sabre\VObject\Component\VCalendar;
+use Sabre\VObject\ITip\Broker;
+use Sabre\VObject\ITip\Message;
+
+class TipBroker extends Broker {
+
+	public $significantChangeProperties = [
+		'DTSTART',
+		'DTEND',
+		'DURATION',
+		'DUE',
+		'RRULE',
+		'RDATE',
+		'EXDATE',
+		'STATUS',
+		'SUMMARY',
+		'DESCRIPTION',
+		'LOCATION',
+
+	];
+
+	/**
+	 * This method is used in cases where an event got updated, and we
+	 * potentially need to send emails to attendees to let them know of updates
+	 * in the events.
+	 *
+	 * We will detect which attendees got added, which got removed and create
+	 * specific messages for these situations.
+	 *
+	 * @return array
+	 */
+	protected function parseEventForOrganizer(VCalendar $calendar, array $eventInfo, array $oldEventInfo) {
+		// Merging attendee lists.
+		$attendees = [];
+		foreach ($oldEventInfo['attendees'] as $attendee) {
+			$attendees[$attendee['href']] = [
+				'href' => $attendee['href'],
+				'oldInstances' => $attendee['instances'],
+				'newInstances' => [],
+				'name' => $attendee['name'],
+				'forceSend' => null,
+			];
+		}
+		foreach ($eventInfo['attendees'] as $attendee) {
+			if (isset($attendees[$attendee['href']])) {
+				$attendees[$attendee['href']]['name'] = $attendee['name'];
+				$attendees[$attendee['href']]['newInstances'] = $attendee['instances'];
+				$attendees[$attendee['href']]['forceSend'] = $attendee['forceSend'];
+			} else {
+				$attendees[$attendee['href']] = [
+					'href' => $attendee['href'],
+					'oldInstances' => [],
+					'newInstances' => $attendee['instances'],
+					'name' => $attendee['name'],
+					'forceSend' => $attendee['forceSend'],
+				];
+			}
+		}
+
+		$messages = [];
+
+		foreach ($attendees as $attendee) {
+			// An organizer can also be an attendee. We should not generate any
+			// messages for those.
+			if ($attendee['href'] === $eventInfo['organizer']) {
+				continue;
+			}
+
+			$message = new Message();
+			$message->uid = $eventInfo['uid'];
+			$message->component = 'VEVENT';
+			$message->sequence = $eventInfo['sequence'];
+			$message->sender = $eventInfo['organizer'];
+			$message->senderName = $eventInfo['organizerName'];
+			$message->recipient = $attendee['href'];
+			$message->recipientName = $attendee['name'];
+
+			// Creating the new iCalendar body.
+			$icalMsg = new VCalendar();
+
+			foreach ($calendar->select('VTIMEZONE') as $timezone) {
+				$icalMsg->add(clone $timezone);
+			}
+			// If there are no instances the attendee is a part of, it means
+			// the attendee was removed and we need to send them a CANCEL message.
+			// Also If the meeting STATUS property was changed to CANCELLED
+			// we need to send the attendee a CANCEL message.
+			if (!$attendee['newInstances'] || $eventInfo['status'] === 'CANCELLED') {
+				
+				$message->method = $icalMsg->METHOD = 'CANCEL';
+				$message->significantChange = true;
+				// clone base event
+				$event = clone $eventInfo['instances']['master'];
+				// alter some properties
+				unset($event->ATTENDEE);
+				$event->add('ATTENDEE', $attendee['href'], ['CN' => $attendee['name'],]);
+				$event->DTSTAMP = gmdate('Ymd\\THis\\Z');
+				$event->SEQUENCE = $message->sequence;
+				$icalMsg->add($event);
+				
+			} else {
+				// The attendee gets the updated event body
+				$message->method = $icalMsg->METHOD = 'REQUEST';
+
+				// We need to find out that this change is significant. If it's
+				// not, systems may opt to not send messages.
+				//
+				// We do this based on the 'significantChangeHash' which is
+				// some value that changes if there's a certain set of
+				// properties changed in the event, or simply if there's a
+				// difference in instances that the attendee is invited to.
+
+				$oldAttendeeInstances = array_keys($attendee['oldInstances']);
+				$newAttendeeInstances = array_keys($attendee['newInstances']);
+
+				$message->significantChange =
+					$attendee['forceSend'] === 'REQUEST' ||
+					count($oldAttendeeInstances) !== count($newAttendeeInstances) ||
+					count(array_diff($oldAttendeeInstances, $newAttendeeInstances)) > 0 ||
+					$oldEventInfo['significantChangeHash'] !== $eventInfo['significantChangeHash'];
+
+				foreach ($attendee['newInstances'] as $instanceId => $instanceInfo) {
+					$currentEvent = clone $eventInfo['instances'][$instanceId];
+					if ($instanceId === 'master') {
+						// We need to find a list of events that the attendee
+						// is not a part of to add to the list of exceptions.
+						$exceptions = [];
+						foreach ($eventInfo['instances'] as $instanceId => $vevent) {
+							if (!isset($attendee['newInstances'][$instanceId])) {
+								$exceptions[] = $instanceId;
+							}
+						}
+
+						// If there were exceptions, we need to add it to an
+						// existing EXDATE property, if it exists.
+						if ($exceptions) {
+							if (isset($currentEvent->EXDATE)) {
+								$currentEvent->EXDATE->setParts(array_merge(
+									$currentEvent->EXDATE->getParts(),
+									$exceptions
+								));
+							} else {
+								$currentEvent->EXDATE = $exceptions;
+							}
+						}
+
+						// Cleaning up any scheduling information that
+						// shouldn't be sent along.
+						unset($currentEvent->ORGANIZER['SCHEDULE-FORCE-SEND']);
+						unset($currentEvent->ORGANIZER['SCHEDULE-STATUS']);
+
+						foreach ($currentEvent->ATTENDEE as $attendee) {
+							unset($attendee['SCHEDULE-FORCE-SEND']);
+							unset($attendee['SCHEDULE-STATUS']);
+
+							// We're adding PARTSTAT=NEEDS-ACTION to ensure that
+							// iOS shows an "Inbox Item"
+							if (!isset($attendee['PARTSTAT'])) {
+								$attendee['PARTSTAT'] = 'NEEDS-ACTION';
+							}
+						}
+					}
+
+					$currentEvent->DTSTAMP = gmdate('Ymd\\THis\\Z');
+					$icalMsg->add($currentEvent);
+				}
+			}
+
+			$message->message = $icalMsg;
+			$messages[] = $message;
+		}
+
+		return $messages;
+	}
+
+}
diff --git a/apps/dav/tests/unit/CalDAV/TipBrokerTest.php b/apps/dav/tests/unit/CalDAV/TipBrokerTest.php
new file mode 100644
index 0000000000000..1a266f5c89c24
--- /dev/null
+++ b/apps/dav/tests/unit/CalDAV/TipBrokerTest.php
@@ -0,0 +1,177 @@
+<?php
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\DAV\Tests\unit\CalDAV;
+
+use OCA\DAV\CalDAV\TipBroker;
+use Sabre\VObject\Component\VCalendar;
+use Test\TestCase;
+
+class TipBrokerTest extends TestCase {
+
+	private TipBroker $broker;
+	private VCalendar $vCalendar1a;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->broker = new TipBroker();
+		// construct calendar with a 1 hour event and same start/end time zones
+		$this->vCalendar1a = new VCalendar();
+		/** @var VEvent $vEvent */
+		$vEvent = $this->vCalendar1a->add('VEVENT', []);
+		$vEvent->add('UID', '96a0e6b1-d886-4a55-a60d-152b31401dcc');
+		$vEvent->add('DTSTAMP', '20240701T000000Z');
+		$vEvent->add('CREATED', '20240701T000000Z');
+		$vEvent->add('LAST-MODIFIED', '20240701T000000Z');
+		$vEvent->add('SEQUENCE', '1');
+		$vEvent->add('STATUS', 'CONFIRMED');
+		$vEvent->add('DTSTART', '20240701T080000', ['TZID' => 'America/Toronto']);
+		$vEvent->add('DTEND', '20240701T090000', ['TZID' => 'America/Toronto']);
+		$vEvent->add('SUMMARY', 'Test Event');
+		$vEvent->add('ORGANIZER', 'mailto:organizer@testing.com', ['CN' => 'Organizer']);
+		$vEvent->add('ATTENDEE', 'mailto:attendee1@testing.com', [
+			'CN' => 'Attendee One',
+			'CUTYPE' => 'INDIVIDUAL',
+			'PARTSTAT' => 'NEEDS-ACTION',
+			'ROLE' => 'REQ-PARTICIPANT',
+			'RSVP' => 'TRUE'
+		]);
+	}
+
+	public function testParseEventForOrganizerOnCreate(): void {
+		
+		// construct calendar and generate event info for newly created event with one attendee
+		$calendar = clone $this->vCalendar1a;
+		$previousEventInfo = [
+			'organizer' => null,
+			'significantChangeHash' => '',
+			'attendees' => [],
+		];
+		$currentEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		// test iTip generation
+		$messages = $this->invokePrivate($this->broker, 'parseEventForOrganizer', [$calendar, $currentEventInfo, $previousEventInfo]);
+		$this->assertCount(1, $messages);
+		$this->assertEquals('REQUEST', $messages[0]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[0]->sender);
+		$this->assertEquals($calendar->VEVENT->ATTENDEE[0]->getValue(), $messages[0]->recipient);
+
+	}
+
+	public function testParseEventForOrganizerOnModify(): void {
+		
+		// construct calendar and generate event info for modified event with one attendee
+		$calendar = clone $this->vCalendar1a;
+		$previousEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		$calendar->VEVENT->{'LAST-MODIFIED'}->setValue('20240701T020000Z');
+		$calendar->VEVENT->SEQUENCE->setValue(2);
+		$calendar->VEVENT->SUMMARY->setValue('Test Event Modified');
+		$currentEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		// test iTip generation
+		$messages = $this->invokePrivate($this->broker, 'parseEventForOrganizer', [$calendar, $currentEventInfo, $previousEventInfo]);
+		$this->assertCount(1, $messages);
+		$this->assertEquals('REQUEST', $messages[0]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[0]->sender);
+		$this->assertEquals($calendar->VEVENT->ATTENDEE[0]->getValue(), $messages[0]->recipient);
+
+	}
+
+	public function testParseEventForOrganizerOnDelete(): void {
+		
+		// construct calendar and generate event info for modified event with one attendee
+		$calendar = clone $this->vCalendar1a;
+		$previousEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		$currentEventInfo = $previousEventInfo;
+		$currentEventInfo['attendees'] = [];
+		++$currentEventInfo['sequence'];
+		// test iTip generation
+		$messages = $this->invokePrivate($this->broker, 'parseEventForOrganizer', [$calendar, $currentEventInfo, $previousEventInfo]);
+		$this->assertCount(1, $messages);
+		$this->assertEquals('CANCEL', $messages[0]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[0]->sender);
+		$this->assertEquals($calendar->VEVENT->ATTENDEE[0]->getValue(), $messages[0]->recipient);
+
+	}
+
+	public function testParseEventForOrganizerOnStatusCancelled(): void {
+		
+		// construct calendar and generate event info for modified event with one attendee
+		$calendar = clone $this->vCalendar1a;
+		$previousEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		$calendar->VEVENT->{'LAST-MODIFIED'}->setValue('20240701T020000Z');
+		$calendar->VEVENT->SEQUENCE->setValue(2);
+		$calendar->VEVENT->STATUS->setValue('CANCELLED');
+		$currentEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		// test iTip generation
+		$messages = $this->invokePrivate($this->broker, 'parseEventForOrganizer', [$calendar, $currentEventInfo, $previousEventInfo]);
+		$this->assertCount(1, $messages);
+		$this->assertEquals('CANCEL', $messages[0]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[0]->sender);
+		$this->assertEquals($calendar->VEVENT->ATTENDEE[0]->getValue(), $messages[0]->recipient);
+
+	}
+
+	public function testParseEventForOrganizerOnAddAttendee(): void {
+		
+		// construct calendar and generate event info for modified event with two attendees
+		$calendar = clone $this->vCalendar1a;
+		$previousEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		$calendar->VEVENT->{'LAST-MODIFIED'}->setValue('20240701T020000Z');
+		$calendar->VEVENT->SEQUENCE->setValue(2);
+		$calendar->VEVENT->add('ATTENDEE', 'mailto:attendee2@testing.com', [
+			'CN' => 'Attendee Two',
+			'CUTYPE' => 'INDIVIDUAL',
+			'PARTSTAT' => 'NEEDS-ACTION',
+			'ROLE' => 'REQ-PARTICIPANT',
+			'RSVP' => 'TRUE'
+		]);
+		$currentEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		// test iTip generation
+		$messages = $this->invokePrivate($this->broker, 'parseEventForOrganizer', [$calendar, $currentEventInfo, $previousEventInfo]);
+		$this->assertCount(2, $messages);
+		$this->assertEquals('REQUEST', $messages[0]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[0]->sender);
+		$this->assertEquals($calendar->VEVENT->ATTENDEE[0]->getValue(), $messages[0]->recipient);
+		$this->assertEquals('REQUEST', $messages[1]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[1]->sender);
+		$this->assertEquals($calendar->VEVENT->ATTENDEE[1]->getValue(), $messages[1]->recipient);
+
+	}
+
+	public function testParseEventForOrganizerOnRemoveAttendee(): void {
+		
+		// construct calendar and generate event info for modified event with two attendees
+		$calendar = clone $this->vCalendar1a;
+		$calendar->VEVENT->add('ATTENDEE', 'mailto:attendee2@testing.com', [
+			'CN' => 'Attendee Two',
+			'CUTYPE' => 'INDIVIDUAL',
+			'PARTSTAT' => 'NEEDS-ACTION',
+			'ROLE' => 'REQ-PARTICIPANT',
+			'RSVP' => 'TRUE'
+		]);
+		$previousEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		$calendar->VEVENT->{'LAST-MODIFIED'}->setValue('20240701T020000Z');
+		$calendar->VEVENT->SEQUENCE->setValue(2);
+		$calendar->VEVENT->remove('ATTENDEE');
+		$calendar->VEVENT->add('ATTENDEE', 'mailto:attendee1@testing.com', [
+			'CN' => 'Attendee One',
+			'CUTYPE' => 'INDIVIDUAL',
+			'PARTSTAT' => 'NEEDS-ACTION',
+			'ROLE' => 'REQ-PARTICIPANT',
+			'RSVP' => 'TRUE'
+		]);
+		$currentEventInfo = $this->invokePrivate($this->broker, 'parseEventInfo', [$calendar]);
+		// test iTip generation
+		$messages = $this->invokePrivate($this->broker, 'parseEventForOrganizer', [$calendar, $currentEventInfo, $previousEventInfo]);
+		$this->assertCount(2, $messages);
+		$this->assertEquals('REQUEST', $messages[0]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[0]->sender);
+		$this->assertEquals($calendar->VEVENT->ATTENDEE[0]->getValue(), $messages[0]->recipient);
+		$this->assertEquals('CANCEL', $messages[1]->method);
+		$this->assertEquals($calendar->VEVENT->ORGANIZER->getValue(), $messages[1]->sender);
+		$this->assertEquals('mailto:attendee2@testing.com', $messages[1]->recipient);
+
+	}
+}
diff --git a/config/config.php-s3 b/config/config.php-s3
new file mode 100644
index 0000000000000..06eb950e61c14
--- /dev/null
+++ b/config/config.php-s3
@@ -0,0 +1,50 @@
+<?php
+$CONFIG = array (
+  'instanceid' => 'oc1y5kb8r5e5',
+  'passwordsalt' => 'a1afwlf9mkGBxmFv0ZdI97rmfn5i+3',
+  'secret' => 'hWqVCcozlJojonOCSHW7Kcy+XKB9ARSHPOJSqFatwCw0w71h',
+  'trusted_domains' => 
+  array (
+    0 => 'nextcloud29',
+  ),
+  //'datadirectory' => '/var/www/nextcloud/stable29/data',
+  'objectstore' => [
+  'class' => '\\OC\\Files\\ObjectStore\\S3',
+        'arguments' => [
+                'bucket' => 'nextcloud29-2',
+                'hostname' => 'localhost',
+                'key' => 'oRrQhpkiBkFtdDQfX5wV',
+                'secret' => 'IOKt6hvSST25TluOx4SYMLwy9be2iGkIhAKMwFWJ',
+                'port' => 9191,
+                // required for some non-Amazon S3 implementations
+                'use_path_style' => true,
+		'use_ssl' => false,
+        ],
+  ],
+  'dbtype' => 'mysql',
+  'version' => '29.0.8.1',
+  'overwrite.cli.url' => 'https://nextcloud29',
+  'dbname' => 'nextcloud29',
+  'dbhost' => 'localhost',
+  'dbport' => '',
+  'dbtableprefix' => 'oc_',
+  'mysql.utf8mb4' => true,
+  'dbuser' => 'nextcloud29',
+  'dbpassword' => 'nextcloud29',
+  'updater.release.channel' => 'git',
+  'installed' => true,
+  'debug' => true,
+  'mail_from_address' => 'ncdev',
+  'mail_smtpmode' => 'smtp',
+  'mail_sendmailmode' => 'smtp',
+  'mail_domain' => 'ksamail.ca',
+  'mail_smtphost' => 'ksamail.ca',
+  'mail_smtpauth' => 1,
+  'mail_smtpport' => '587',
+  'mail_smtpname' => 'ncdev@ksamail.ca',
+  'mail_smtppassword' => '3e0645Md1',
+  'theme' => '',
+  'loglevel' => 2,
+  'maintenance' => false,
+  'debug' => true,
+);