diff --git a/CHANGELOG.md b/CHANGELOG.md
index b9dc083..36c19a9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,10 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## 4.0.0
+### Removed
+- Nextcloud <21 support
+
 ## 3.3.2
 ### Added
 - Possible url for SLO response
diff --git a/appinfo/info.xml b/appinfo/info.xml
index f999340..86c5af2 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -16,7 +16,7 @@ The following providers are supported and tested at the moment:
 	* Any other provider that authenticates using the environment variable
 
 While theoretically any other authentication provider implementing either one of those standards is compatible, we like to note that they are not part of any internal test matrix.]]></description>
-	<version>3.3.2</version>
+	<version>4.0.0</version>
 	<licence>agpl</licence>
 	<author>Lukas Reschke</author>
 	<namespace>User_SAML</namespace>
@@ -33,7 +33,7 @@ While theoretically any other authentication provider implementing either one of
 	<screenshot>https://raw.githubusercontent.com/nextcloud/user_saml/master/screenshots/1.png</screenshot>
 	<screenshot>https://raw.githubusercontent.com/nextcloud/user_saml/master/screenshots/2.png</screenshot>
 	<dependencies>
-		<nextcloud min-version="20" max-version="21" />
+		<nextcloud min-version="21" max-version="21" />
 	</dependencies>
 	<commands>
 		<command>OCA\User_SAML\Command\GetMetadata</command>
diff --git a/lib/Migration/Version3001Date20200630193443.php b/lib/Migration/Version3001Date20200630193443.php
index de709be..df1a2cc 100644
--- a/lib/Migration/Version3001Date20200630193443.php
+++ b/lib/Migration/Version3001Date20200630193443.php
@@ -26,8 +26,8 @@ declare(strict_types=1);
 namespace OCA\User_SAML\Migration;
 
 use Closure;
-use Doctrine\DBAL\Types\Type;
 use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
 use OCP\Migration\IOutput;
 use OCP\Migration\SimpleMigrationStep;
 
@@ -44,17 +44,17 @@ class Version3001Date20200630193443 extends SimpleMigrationStep {
 
 		if (!$schema->hasTable('user_saml_users')) {
 			$table = $schema->createTable('user_saml_users');
-			$table->addColumn('uid', Type::STRING, [
+			$table->addColumn('uid', Types::STRING, [
 				'notnull' => true,
 				'length' => 64,
 				'default' => '',
 			]);
-			$table->addColumn('displayname', Type::STRING, [
+			$table->addColumn('displayname', Types::STRING, [
 				'notnull' => true,
 				'length' => 255,
 				'default' => '',
 			]);
-			$table->addColumn('home', Type::STRING, [
+			$table->addColumn('home', Types::STRING, [
 				'notnull' => true,
 				'length' => 255,
 				'default' => '',
@@ -64,22 +64,22 @@ class Version3001Date20200630193443 extends SimpleMigrationStep {
 
 		if (!$schema->hasTable('user_saml_auth_token')) {
 			$table = $schema->createTable('user_saml_auth_token');
-			$table->addColumn('id', Type::INTEGER, [
+			$table->addColumn('id', Types::INTEGER, [
 				'autoincrement' => true,
 				'notnull' => true,
 				'length' => 4,
 				'unsigned' => true,
 			]);
-			$table->addColumn('uid', Type::STRING, [
+			$table->addColumn('uid', Types::STRING, [
 				'notnull' => true,
 				'length' => 64,
 				'default' => '',
 			]);
-			$table->addColumn('name', Type::TEXT, [
+			$table->addColumn('name', Types::TEXT, [
 				'notnull' => true,
 				'default' => '',
 			]);
-			$table->addColumn('token', Type::STRING, [
+			$table->addColumn('token', Types::STRING, [
 				'notnull' => true,
 				'length' => 200,
 				'default' => '',