diff --git a/apps/accessibility/composer/composer/ClassLoader.php b/apps/accessibility/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/accessibility/composer/composer/ClassLoader.php
+++ b/apps/accessibility/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/admin_audit/composer/composer/ClassLoader.php b/apps/admin_audit/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/admin_audit/composer/composer/ClassLoader.php
+++ b/apps/admin_audit/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/cloud_federation_api/composer/composer/ClassLoader.php b/apps/cloud_federation_api/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/cloud_federation_api/composer/composer/ClassLoader.php
+++ b/apps/cloud_federation_api/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/comments/composer/composer/ClassLoader.php b/apps/comments/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/comments/composer/composer/ClassLoader.php
+++ b/apps/comments/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/contactsinteraction/composer/composer/ClassLoader.php b/apps/contactsinteraction/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/contactsinteraction/composer/composer/ClassLoader.php
+++ b/apps/contactsinteraction/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/dav/appinfo/info.xml b/apps/dav/appinfo/info.xml
index 9eab8e3270..b0bcc782d9 100644
--- a/apps/dav/appinfo/info.xml
+++ b/apps/dav/appinfo/info.xml
@@ -5,7 +5,7 @@
 	<name>WebDAV</name>
 	<summary>WebDAV endpoint</summary>
 	<description>WebDAV endpoint</description>
-	<version>1.16.0</version>
+	<version>1.16.1</version>
 	<licence>agpl</licence>
 	<author>owncloud.org</author>
 	<namespace>DAV</namespace>
diff --git a/apps/dav/composer/composer/ClassLoader.php b/apps/dav/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/dav/composer/composer/ClassLoader.php
+++ b/apps/dav/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index aaa5e82da0..e0684f0c79 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -230,6 +230,7 @@ return array(
     'OCA\\DAV\\Migration\\Version1011Date20190725113607' => $baseDir . '/../lib/Migration/Version1011Date20190725113607.php',
     'OCA\\DAV\\Migration\\Version1011Date20190806104428' => $baseDir . '/../lib/Migration/Version1011Date20190806104428.php',
     'OCA\\DAV\\Migration\\Version1012Date20190808122342' => $baseDir . '/../lib/Migration/Version1012Date20190808122342.php',
+    'OCA\\DAV\\Migration\\Version1016Date20201109085907' => $baseDir . '/../lib/Migration/Version1016Date20201109085907.php',
     'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningNode' => $baseDir . '/../lib/Provisioning/Apple/AppleProvisioningNode.php',
     'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningPlugin' => $baseDir . '/../lib/Provisioning/Apple/AppleProvisioningPlugin.php',
     'OCA\\DAV\\RootCollection' => $baseDir . '/../lib/RootCollection.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index 0dc34f5a31..32b5e03a3f 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -245,6 +245,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Migration\\Version1011Date20190725113607' => __DIR__ . '/..' . '/../lib/Migration/Version1011Date20190725113607.php',
         'OCA\\DAV\\Migration\\Version1011Date20190806104428' => __DIR__ . '/..' . '/../lib/Migration/Version1011Date20190806104428.php',
         'OCA\\DAV\\Migration\\Version1012Date20190808122342' => __DIR__ . '/..' . '/../lib/Migration/Version1012Date20190808122342.php',
+        'OCA\\DAV\\Migration\\Version1016Date20201109085907' => __DIR__ . '/..' . '/../lib/Migration/Version1016Date20201109085907.php',
         'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningNode' => __DIR__ . '/..' . '/../lib/Provisioning/Apple/AppleProvisioningNode.php',
         'OCA\\DAV\\Provisioning\\Apple\\AppleProvisioningPlugin' => __DIR__ . '/..' . '/../lib/Provisioning/Apple/AppleProvisioningPlugin.php',
         'OCA\\DAV\\RootCollection' => __DIR__ . '/..' . '/../lib/RootCollection.php',
diff --git a/apps/dav/lib/Migration/Version1012Date20190808122342.php b/apps/dav/lib/Migration/Version1012Date20190808122342.php
index 7aa51a224e..51929d1a2f 100644
--- a/apps/dav/lib/Migration/Version1012Date20190808122342.php
+++ b/apps/dav/lib/Migration/Version1012Date20190808122342.php
@@ -69,7 +69,7 @@ class Version1012Date20190808122342 extends SimpleMigrationStep {
 				'length' => 11,
 			]);
 			$table->addColumn('is_recurring', Types::SMALLINT, [
-				'notnull' => true,
+				'notnull' => false,
 				'length' => 1,
 			]);
 			$table->addColumn('uid', Types::STRING, [
diff --git a/apps/dav/lib/Migration/Version1016Date20201109085907.php b/apps/dav/lib/Migration/Version1016Date20201109085907.php
new file mode 100644
index 0000000000..a43c8ae06a
--- /dev/null
+++ b/apps/dav/lib/Migration/Version1016Date20201109085907.php
@@ -0,0 +1,60 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\DAV\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version1016Date20201109085907 extends SimpleMigrationStep {
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$result = $this->ensureColumnIsNullable($schema, 'calendar_reminders', 'is_recurring');
+
+		return $result ? $schema : null;
+	}
+
+	protected function ensureColumnIsNullable(ISchemaWrapper $schema, string $tableName, string $columnName): bool {
+		$table = $schema->getTable($tableName);
+		$column = $table->getColumn($columnName);
+
+		if ($column->getNotnull()) {
+			$column->setNotnull(false);
+			return true;
+		}
+
+		return false;
+	}
+}
diff --git a/apps/encryption/composer/composer/ClassLoader.php b/apps/encryption/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/encryption/composer/composer/ClassLoader.php
+++ b/apps/encryption/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/federatedfilesharing/composer/composer/ClassLoader.php b/apps/federatedfilesharing/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/federatedfilesharing/composer/composer/ClassLoader.php
+++ b/apps/federatedfilesharing/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/federation/composer/composer/ClassLoader.php b/apps/federation/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/federation/composer/composer/ClassLoader.php
+++ b/apps/federation/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/files/composer/composer/ClassLoader.php b/apps/files/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/files/composer/composer/ClassLoader.php
+++ b/apps/files/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/files_sharing/composer/composer/ClassLoader.php b/apps/files_sharing/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/files_sharing/composer/composer/ClassLoader.php
+++ b/apps/files_sharing/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/files_trashbin/composer/composer/ClassLoader.php b/apps/files_trashbin/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/files_trashbin/composer/composer/ClassLoader.php
+++ b/apps/files_trashbin/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/files_versions/composer/composer/ClassLoader.php b/apps/files_versions/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/files_versions/composer/composer/ClassLoader.php
+++ b/apps/files_versions/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/lookup_server_connector/composer/composer/ClassLoader.php b/apps/lookup_server_connector/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/lookup_server_connector/composer/composer/ClassLoader.php
+++ b/apps/lookup_server_connector/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/oauth2/composer/composer/ClassLoader.php b/apps/oauth2/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/oauth2/composer/composer/ClassLoader.php
+++ b/apps/oauth2/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/provisioning_api/composer/composer/ClassLoader.php b/apps/provisioning_api/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/provisioning_api/composer/composer/ClassLoader.php
+++ b/apps/provisioning_api/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/settings/composer/composer/ClassLoader.php b/apps/settings/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/settings/composer/composer/ClassLoader.php
+++ b/apps/settings/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/sharebymail/composer/composer/ClassLoader.php b/apps/sharebymail/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/sharebymail/composer/composer/ClassLoader.php
+++ b/apps/sharebymail/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/systemtags/composer/composer/ClassLoader.php b/apps/systemtags/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/systemtags/composer/composer/ClassLoader.php
+++ b/apps/systemtags/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/testing/composer/composer/ClassLoader.php b/apps/testing/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/testing/composer/composer/ClassLoader.php
+++ b/apps/testing/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/twofactor_backupcodes/composer/composer/ClassLoader.php b/apps/twofactor_backupcodes/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/twofactor_backupcodes/composer/composer/ClassLoader.php
+++ b/apps/twofactor_backupcodes/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/updatenotification/composer/composer/ClassLoader.php b/apps/updatenotification/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/updatenotification/composer/composer/ClassLoader.php
+++ b/apps/updatenotification/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/user_ldap/composer/composer/ClassLoader.php b/apps/user_ldap/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/user_ldap/composer/composer/ClassLoader.php
+++ b/apps/user_ldap/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/user_status/composer/composer/ClassLoader.php b/apps/user_status/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/user_status/composer/composer/ClassLoader.php
+++ b/apps/user_status/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/apps/workflowengine/composer/composer/ClassLoader.php b/apps/workflowengine/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/apps/workflowengine/composer/composer/ClassLoader.php
+++ b/apps/workflowengine/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/core/Migrations/Version13000Date20170718121200.php b/core/Migrations/Version13000Date20170718121200.php
index f3129c22ca..fcea6657b3 100644
--- a/core/Migrations/Version13000Date20170718121200.php
+++ b/core/Migrations/Version13000Date20170718121200.php
@@ -813,7 +813,7 @@ class Version13000Date20170718121200 extends SimpleMigrationStep {
 		if (!$schema->hasTable('credentials')) {
 			$table = $schema->createTable('credentials');
 			$table->addColumn('user', 'string', [
-				'notnull' => true,
+				'notnull' => false,
 				'length' => 64,
 			]);
 			$table->addColumn('identifier', 'string', [
diff --git a/core/Migrations/Version14000Date20180710092004.php b/core/Migrations/Version14000Date20180710092004.php
index 141b0c1afb..767d8ee5f7 100644
--- a/core/Migrations/Version14000Date20180710092004.php
+++ b/core/Migrations/Version14000Date20180710092004.php
@@ -43,6 +43,7 @@ class Version14000Date20180710092004 extends SimpleMigrationStep {
 		if (!$table->hasColumn('password_by_talk')) {
 			$table->addColumn('password_by_talk', Types::BOOLEAN, [
 				'default' => 0,
+				'notnull' => false,
 			]);
 		}
 
diff --git a/core/Migrations/Version15000Date20180926101451.php b/core/Migrations/Version15000Date20180926101451.php
index a5f37cc912..e03a11318c 100644
--- a/core/Migrations/Version15000Date20180926101451.php
+++ b/core/Migrations/Version15000Date20180926101451.php
@@ -45,8 +45,8 @@ class Version15000Date20180926101451 extends SimpleMigrationStep {
 
 		$table = $schema->getTable('authtoken');
 		$table->addColumn('password_invalid','boolean', [
-			'notnull' => true,
-			'default' => false,
+			'default' => 0,
+			'notnull' => false,
 		]);
 
 		return $schema;
diff --git a/core/Migrations/Version15000Date20181015062942.php b/core/Migrations/Version15000Date20181015062942.php
index eaeaf0dd26..23c2a90474 100644
--- a/core/Migrations/Version15000Date20181015062942.php
+++ b/core/Migrations/Version15000Date20181015062942.php
@@ -45,7 +45,7 @@ class Version15000Date20181015062942 extends SimpleMigrationStep {
 
 		$table = $schema->getTable('share');
 		$table->addColumn('hide_download', 'smallint', [
-			'notnull' => true,
+			'notnull' => false,
 			'length' => 1,
 			'default' => 0,
 		]);
diff --git a/core/Migrations/Version16000Date20190207141427.php b/core/Migrations/Version16000Date20190207141427.php
index e6235efe20..63c6c871ea 100644
--- a/core/Migrations/Version16000Date20190207141427.php
+++ b/core/Migrations/Version16000Date20190207141427.php
@@ -102,7 +102,7 @@ class Version16000Date20190207141427 extends SimpleMigrationStep {
 				'default' => '',
 			]);
 			$table->addColumn('access', Types::SMALLINT, [
-				'notnull' => true,
+				'notnull' => false,
 				'default' => 0,
 			]);
 
diff --git a/core/Migrations/Version16000Date20190428150708.php b/core/Migrations/Version16000Date20190428150708.php
index 546d4c19e1..dc33b08035 100644
--- a/core/Migrations/Version16000Date20190428150708.php
+++ b/core/Migrations/Version16000Date20190428150708.php
@@ -49,7 +49,7 @@ class Version16000Date20190428150708 extends SimpleMigrationStep {
 		if ($schema->hasTable('collres_accesscache')) {
 			$table = $schema->getTable('collres_accesscache');
 			$table->addColumn('access', Types::BOOLEAN, [
-				'notnull' => true,
+				'notnull' => false,
 				'default' => false
 			]);
 		}
diff --git a/core/Migrations/Version20000Date20201109081915.php b/core/Migrations/Version20000Date20201109081915.php
new file mode 100644
index 0000000000..720f54d8e8
--- /dev/null
+++ b/core/Migrations/Version20000Date20201109081915.php
@@ -0,0 +1,64 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2020 Joas Schilling <coding@schilljs.com>
+ *
+ * @author Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OC\Core\Migrations;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version20000Date20201109081915 extends SimpleMigrationStep {
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$result = $this->ensureColumnIsNullable($schema, 'share', 'password_by_talk');
+		$result = $this->ensureColumnIsNullable($schema, 'share', 'hide_download') || $result;
+		$result = $this->ensureColumnIsNullable($schema, 'credentials', 'user') || $result;
+		$result = $this->ensureColumnIsNullable($schema, 'authtoken', 'password_invalid') || $result;
+		$result = $this->ensureColumnIsNullable($schema, 'collres_accesscache', 'access') || $result;
+
+		return $result ? $schema : null;
+	}
+
+	protected function ensureColumnIsNullable(ISchemaWrapper $schema, string $tableName, string $columnName): bool {
+		$table = $schema->getTable($tableName);
+		$column = $table->getColumn($columnName);
+
+		if ($column->getNotnull()) {
+			$column->setNotnull(false);
+			return true;
+		}
+
+		return false;
+	}
+}
diff --git a/lib/composer/composer/ClassLoader.php b/lib/composer/composer/ClassLoader.php
index fce8549f07..03b9bb9c40 100644
--- a/lib/composer/composer/ClassLoader.php
+++ b/lib/composer/composer/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index f28e7977a0..48f9f60999 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -919,6 +919,7 @@ return array(
     'OC\\Core\\Migrations\\Version18000Date20191014105105' => $baseDir . '/core/Migrations/Version18000Date20191014105105.php',
     'OC\\Core\\Migrations\\Version18000Date20191204114856' => $baseDir . '/core/Migrations/Version18000Date20191204114856.php',
     'OC\\Core\\Migrations\\Version19000Date20200211083441' => $baseDir . '/core/Migrations/Version19000Date20200211083441.php',
+    'OC\\Core\\Migrations\\Version20000Date20201109081915' => $baseDir . '/core/Migrations/Version20000Date20201109081915.php',
     'OC\\Core\\Notification\\RemoveLinkSharesNotifier' => $baseDir . '/core/Notification/RemoveLinkSharesNotifier.php',
     'OC\\Core\\Service\\LoginFlowV2Service' => $baseDir . '/core/Service/LoginFlowV2Service.php',
     'OC\\DB\\Adapter' => $baseDir . '/lib/private/DB/Adapter.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index e584c63c64..c6f23f1852 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -948,6 +948,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\Core\\Migrations\\Version18000Date20191014105105' => __DIR__ . '/../../..' . '/core/Migrations/Version18000Date20191014105105.php',
         'OC\\Core\\Migrations\\Version18000Date20191204114856' => __DIR__ . '/../../..' . '/core/Migrations/Version18000Date20191204114856.php',
         'OC\\Core\\Migrations\\Version19000Date20200211083441' => __DIR__ . '/../../..' . '/core/Migrations/Version19000Date20200211083441.php',
+        'OC\\Core\\Migrations\\Version20000Date20201109081915' => __DIR__ . '/../../..' . '/core/Migrations/Version20000Date20201109081915.php',
         'OC\\Core\\Notification\\RemoveLinkSharesNotifier' => __DIR__ . '/../../..' . '/core/Notification/RemoveLinkSharesNotifier.php',
         'OC\\Core\\Service\\LoginFlowV2Service' => __DIR__ . '/../../..' . '/core/Service/LoginFlowV2Service.php',
         'OC\\DB\\Adapter' => __DIR__ . '/../../..' . '/lib/private/DB/Adapter.php',
diff --git a/version.php b/version.php
index 9b82df9ca0..f971a54fa1 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 // between betas, final and RCs. This is _not_ the public version number. Reset minor/patchlevel
 // when updating major/minor version number.
 
-$OC_Version = [20, 0, 1, 1];
+$OC_Version = [20, 0, 1, 4];
 
 // The human readable string
 $OC_VersionString = '20.0.1';