diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index 863b6353f9485..6c67cc53ecbc4 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -414,6 +414,7 @@
     'OCA\\DAV\\Migration\\Version1036Date20251202000000' => $baseDir . '/../lib/Migration/Version1036Date20251202000000.php',
     'OCA\\DAV\\Migration\\Version1038Date20260302000000' => $baseDir . '/../lib/Migration/Version1038Date20260302000000.php',
     'OCA\\DAV\\Migration\\Version1039Date20260408000000' => $baseDir . '/../lib/Migration/Version1039Date20260408000000.php',
+    'OCA\\DAV\\Migration\\Version1039Date20260408000001' => $baseDir . '/../lib/Migration/Version1039Date20260408000001.php',
     'OCA\\DAV\\Migration\\Version1040Date20260805000000' => $baseDir . '/../lib/Migration/Version1040Date20260805000000.php',
     'OCA\\DAV\\Model\\ExampleEvent' => $baseDir . '/../lib/Model/ExampleEvent.php',
     'OCA\\DAV\\Paginate\\LimitedCopyIterator' => $baseDir . '/../lib/Paginate/LimitedCopyIterator.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index c8529e96869b7..11a84fd99449d 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -429,6 +429,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Migration\\Version1036Date20251202000000' => __DIR__ . '/..' . '/../lib/Migration/Version1036Date20251202000000.php',
         'OCA\\DAV\\Migration\\Version1038Date20260302000000' => __DIR__ . '/..' . '/../lib/Migration/Version1038Date20260302000000.php',
         'OCA\\DAV\\Migration\\Version1039Date20260408000000' => __DIR__ . '/..' . '/../lib/Migration/Version1039Date20260408000000.php',
+        'OCA\\DAV\\Migration\\Version1039Date20260408000001' => __DIR__ . '/..' . '/../lib/Migration/Version1039Date20260408000001.php',
         'OCA\\DAV\\Migration\\Version1040Date20260805000000' => __DIR__ . '/..' . '/../lib/Migration/Version1040Date20260805000000.php',
         'OCA\\DAV\\Model\\ExampleEvent' => __DIR__ . '/..' . '/../lib/Model/ExampleEvent.php',
         'OCA\\DAV\\Paginate\\LimitedCopyIterator' => __DIR__ . '/..' . '/../lib/Paginate/LimitedCopyIterator.php',
diff --git a/apps/dav/lib/Migration/Version1039Date20260408000000.php b/apps/dav/lib/Migration/Version1039Date20260408000000.php
index e3dbca8f65217..8031eab55ab43 100644
--- a/apps/dav/lib/Migration/Version1039Date20260408000000.php
+++ b/apps/dav/lib/Migration/Version1039Date20260408000000.php
@@ -14,11 +14,9 @@
 use OCP\DB\Types;
 use OCP\Migration\Attributes\AddColumn;
 use OCP\Migration\Attributes\ColumnType;
-use OCP\Migration\Attributes\DropColumn;
 use OCP\Migration\IOutput;
 use OCP\Migration\SimpleMigrationStep;
 
-#[DropColumn(table: 'calendars', name: 'default_alarm', description: 'Replaced by default_alarm_pday and default_alarm_fday')]
 #[AddColumn(table: 'calendars', name: 'default_alarm_pday', type: ColumnType::INTEGER)]
 #[AddColumn(table: 'calendars', name: 'default_alarm_fday', type: ColumnType::INTEGER)]
 class Version1039Date20260408000000 extends SimpleMigrationStep {
@@ -29,10 +27,6 @@ public function changeSchema(IOutput $output, Closure $schemaClosure, array $opt
 
 		$calendarsTable = $schema->getTable('calendars');
 
-		if ($calendarsTable->hasColumn('default_alarm')) {
-			$calendarsTable->dropColumn('default_alarm');
-		}
-
 		if (!$calendarsTable->hasColumn('default_alarm_pday')) {
 			$calendarsTable->addColumn('default_alarm_pday', Types::INTEGER, [
 				'notnull' => false,
diff --git a/apps/dav/lib/Migration/Version1039Date20260408000001.php b/apps/dav/lib/Migration/Version1039Date20260408000001.php
new file mode 100644
index 0000000000000..147bd413d2501
--- /dev/null
+++ b/apps/dav/lib/Migration/Version1039Date20260408000001.php
@@ -0,0 +1,39 @@
+<?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\Migration\Attributes\DropColumn;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+use Override;
+
+/**
+ * Drops default_alarm in a separate step from adding its replacements, as
+ * dropping and adding columns with the same definition in one step lets the
+ * schema comparator turn them into a rename, which fails on Oracle.
+ */
+#[DropColumn(table: 'calendars', name: 'default_alarm', description: 'Replaced by default_alarm_pday and default_alarm_fday')]
+class Version1039Date20260408000001 extends SimpleMigrationStep {
+	#[Override]
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$calendarsTable = $schema->getTable('calendars');
+		if (!$calendarsTable->hasColumn('default_alarm')) {
+			return null;
+		}
+
+		$calendarsTable->dropColumn('default_alarm');
+		return $schema;
+	}
+}