diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index c010a3e98d602..9c6a2e7598f75 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -389,6 +389,7 @@
     'OCA\\DAV\\Migration\\Version1034Date20250605132605' => $baseDir . '/../lib/Migration/Version1034Date20250605132605.php',
     'OCA\\DAV\\Migration\\Version1034Date20250813093701' => $baseDir . '/../lib/Migration/Version1034Date20250813093701.php',
     'OCA\\DAV\\Migration\\Version1036Date20251202000000' => $baseDir . '/../lib/Migration/Version1036Date20251202000000.php',
+    'OCA\\DAV\\Migration\\Version1037Date20260302000000' => $baseDir . '/../lib/Migration/Version1037Date20260302000000.php',
     'OCA\\DAV\\Model\\ExampleEvent' => $baseDir . '/../lib/Model/ExampleEvent.php',
     'OCA\\DAV\\Paginate\\LimitedCopyIterator' => $baseDir . '/../lib/Paginate/LimitedCopyIterator.php',
     'OCA\\DAV\\Paginate\\PaginateCache' => $baseDir . '/../lib/Paginate/PaginateCache.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index bdb965aab3ee0..f4c4c05170b39 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -7,14 +7,14 @@
 class ComposerStaticInitDAV
 {
     public static $prefixLengthsPsr4 = array (
-        'O' =>
+        'O' => 
         array (
             'OCA\\DAV\\' => 8,
         ),
     );
 
     public static $prefixDirsPsr4 = array (
-        'OCA\\DAV\\' =>
+        'OCA\\DAV\\' => 
         array (
             0 => __DIR__ . '/..' . '/../lib',
         ),
@@ -404,6 +404,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Migration\\Version1034Date20250605132605' => __DIR__ . '/..' . '/../lib/Migration/Version1034Date20250605132605.php',
         'OCA\\DAV\\Migration\\Version1034Date20250813093701' => __DIR__ . '/..' . '/../lib/Migration/Version1034Date20250813093701.php',
         'OCA\\DAV\\Migration\\Version1036Date20251202000000' => __DIR__ . '/..' . '/../lib/Migration/Version1036Date20251202000000.php',
+        'OCA\\DAV\\Migration\\Version1037Date20260302000000' => __DIR__ . '/..' . '/../lib/Migration/Version1037Date20260302000000.php',
         'OCA\\DAV\\Model\\ExampleEvent' => __DIR__ . '/..' . '/../lib/Model/ExampleEvent.php',
         'OCA\\DAV\\Paginate\\LimitedCopyIterator' => __DIR__ . '/..' . '/../lib/Paginate/LimitedCopyIterator.php',
         'OCA\\DAV\\Paginate\\PaginateCache' => __DIR__ . '/..' . '/../lib/Paginate/PaginateCache.php',
diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index 117a79cb0fda5..79bee517befa4 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -151,6 +151,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 		'{http://apple.com/ns/ical/}calendar-order' => ['calendarorder', 'int'],
 		'{http://apple.com/ns/ical/}calendar-color' => ['calendarcolor', 'string'],
 		'{' . \OCA\DAV\DAV\Sharing\Plugin::NS_NEXTCLOUD . '}deleted-at' => ['deleted_at', 'int'],
+		'{' . \OCA\DAV\DAV\Sharing\Plugin::NS_NEXTCLOUD . '}default-alarm' => ['default_alarm', 'string'],
 	];
 
 	/**
diff --git a/apps/dav/lib/Migration/Version1037Date20260302000000.php b/apps/dav/lib/Migration/Version1037Date20260302000000.php
new file mode 100644
index 0000000000000..8be50eedd76ef
--- /dev/null
+++ b/apps/dav/lib/Migration/Version1037Date20260302000000.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\DAV\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\Attributes\AddColumn;
+use OCP\Migration\Attributes\ColumnType;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+#[AddColumn(table: 'calendars', name: 'default_alarm', type: ColumnType::STRING)]
+class Version1037Date20260302000000 extends SimpleMigrationStep {
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$calendarsTable = $schema->getTable('calendars');
+
+		if (!$calendarsTable->hasColumn('default_alarm')) {
+			$calendarsTable->addColumn('default_alarm', Types::INTEGER, [
+				'notnull' => false,
+				'length' => 10,
+				'default' => null,
+			]);
+		}
+
+		return $schema;
+	}
+}
diff --git a/apps/dav/tests/unit/CalDAV/CalDavBackendTest.php b/apps/dav/tests/unit/CalDAV/CalDavBackendTest.php
index 802e73208b0e6..9a19615860dde 100644
--- a/apps/dav/tests/unit/CalDAV/CalDavBackendTest.php
+++ b/apps/dav/tests/unit/CalDAV/CalDavBackendTest.php
@@ -1881,4 +1881,43 @@ public function testUnshare(): void {
 		);
 
 	}
+
+	public function testDefaultAlarmProperty(): void {
+		$calendarId = $this->createTestCalendar();
+
+		// Test setting default alarm property to 15 minutes before (-900 seconds)
+		$patch = new PropPatch([
+			'{http://nextcloud.com/ns}default-alarm' => '-900'
+		]);
+		$this->backend->updateCalendar($calendarId, $patch);
+		$patch->commit();
+
+		// Verify the property was set
+		$calendars = $this->backend->getCalendarsForUser(self::UNIT_TEST_USER);
+		$this->assertCount(1, $calendars);
+		$this->assertEquals('-900', $calendars[0]['{http://nextcloud.com/ns}default-alarm']);
+
+		// Test updating to a different value (1 day before = -86400 seconds)
+		$patch = new PropPatch([
+			'{http://nextcloud.com/ns}default-alarm' => '-86400'
+		]);
+		$this->backend->updateCalendar($calendarId, $patch);
+		$patch->commit();
+
+		$calendars = $this->backend->getCalendarsForUser(self::UNIT_TEST_USER);
+		$this->assertEquals('-86400', $calendars[0]['{http://nextcloud.com/ns}default-alarm']);
+
+		// Test setting to null
+		$patch = new PropPatch([
+			'{http://nextcloud.com/ns}default-alarm' => null
+		]);
+		$this->backend->updateCalendar($calendarId, $patch);
+		$patch->commit();
+
+		$calendars = $this->backend->getCalendarsForUser(self::UNIT_TEST_USER);
+		$this->assertEquals(null, $calendars[0]['{http://nextcloud.com/ns}default-alarm']);
+
+		// Clean up
+		$this->backend->deleteCalendar($calendars[0]['id'], true);
+	}
 }