diff --git a/apps/dav/tests/unit/CalDAV/ResourceBooking/ResourcePrincipalBackendTest.php b/apps/dav/tests/unit/CalDAV/ResourceBooking/ResourcePrincipalBackendTest.php
index 9a877bc348..a92fdb8eb8 100644
--- a/apps/dav/tests/unit/CalDAV/ResourceBooking/ResourcePrincipalBackendTest.php
+++ b/apps/dav/tests/unit/CalDAV/ResourceBooking/ResourcePrincipalBackendTest.php
@@ -26,7 +26,7 @@ namespace OCA\DAV\Tests\unit\CalDAV\ResourceBooking;
 
 use OCA\DAV\CalDAV\ResourceBooking\ResourcePrincipalBackend;
 
-Class ResourcePrincipalBackendTest extends AbstractPrincipalBackendTest {
+class ResourcePrincipalBackendTest extends AbstractPrincipalBackendTest {
 	protected function setUp(): void {
 		parent::setUp();
 
diff --git a/apps/dav/tests/unit/CalDAV/ResourceBooking/RoomPrincipalBackendTest.php b/apps/dav/tests/unit/CalDAV/ResourceBooking/RoomPrincipalBackendTest.php
index 7a7ebad20c..575dac2bed 100644
--- a/apps/dav/tests/unit/CalDAV/ResourceBooking/RoomPrincipalBackendTest.php
+++ b/apps/dav/tests/unit/CalDAV/ResourceBooking/RoomPrincipalBackendTest.php
@@ -26,7 +26,7 @@ namespace OCA\DAV\Tests\unit\CalDAV\ResourceBooking;
 
 use OCA\DAV\CalDAV\ResourceBooking\RoomPrincipalBackend;
 
-Class RoomPrincipalBackendTest extends AbstractPrincipalBackendTest {
+class RoomPrincipalBackendTest extends AbstractPrincipalBackendTest {
 	protected function setUp(): void {
 		parent::setUp();
 
diff --git a/apps/files_external/lib/Controller/UserStoragesController.php b/apps/files_external/lib/Controller/UserStoragesController.php
index 345bd3e855..787e7affaf 100644
--- a/apps/files_external/lib/Controller/UserStoragesController.php
+++ b/apps/files_external/lib/Controller/UserStoragesController.php
@@ -135,7 +135,7 @@ class UserStoragesController extends StoragesController {
 			$backendOptions,
 			$mountOptions
 		);
-		if ($newStorage instanceOf DataResponse) {
+		if ($newStorage instanceof DataResponse) {
 			return $newStorage;
 		}
 
@@ -184,7 +184,7 @@ class UserStoragesController extends StoragesController {
 			$backendOptions,
 			$mountOptions
 		);
-		if ($storage instanceOf DataResponse) {
+		if ($storage instanceof DataResponse) {
 			return $storage;
 		}
 		$storage->setId($id);
diff --git a/apps/files_sharing/lib/Controller/DeletedShareAPIController.php b/apps/files_sharing/lib/Controller/DeletedShareAPIController.php
index 5f31459384..b109a6282f 100644
--- a/apps/files_sharing/lib/Controller/DeletedShareAPIController.php
+++ b/apps/files_sharing/lib/Controller/DeletedShareAPIController.php
@@ -121,7 +121,7 @@ class DeletedShareAPIController extends OCSController {
 		}
 
 		$result['path'] = $userFolder->getRelativePath($node->getPath());
-		if ($node instanceOf \OCP\Files\Folder) {
+		if ($node instanceof \OCP\Files\Folder) {
 			$result['item_type'] = 'folder';
 		} else {
 			$result['item_type'] = 'file';
diff --git a/apps/user_ldap/lib/Mapping/AbstractMapping.php b/apps/user_ldap/lib/Mapping/AbstractMapping.php
index 14075da5c0..5d445af6b7 100644
--- a/apps/user_ldap/lib/Mapping/AbstractMapping.php
+++ b/apps/user_ldap/lib/Mapping/AbstractMapping.php
@@ -289,7 +289,7 @@ abstract class AbstractMapping {
 	 * @return bool true on success, false when at least one row was not
 	 * deleted
 	 */
-	public function clearCb(Callable $preCallback, Callable $postCallback): bool {
+	public function clearCb(callable $preCallback, callable $postCallback): bool {
 		$picker = $this->dbc->getQueryBuilder();
 		$picker->select('owncloud_name')
 			->from($this->getTableName());
diff --git a/core/Controller/SetupController.php b/core/Controller/SetupController.php
index 7449717831..7df02dfea0 100644
--- a/core/Controller/SetupController.php
+++ b/core/Controller/SetupController.php
@@ -70,7 +70,7 @@ class SetupController {
 			return;
 		}
 
-		if(isset($post['install']) AND $post['install']=='true') {
+		if(isset($post['install']) and $post['install']=='true') {
 			// We have to launch the installation process :
 			$e = $this->setupHelper->install($post);
 			$errors = ['errors' => $e];
@@ -141,7 +141,7 @@ class SetupController {
 		$directoryIsSet = isset($post['directory']);
 		$adminAccountIsSet = isset($post['adminlogin']);
 
-		if ($dbIsSet AND $directoryIsSet AND $adminAccountIsSet) {
+		if ($dbIsSet and $directoryIsSet and $adminAccountIsSet) {
 			$post['install'] = 'true';
 		}
 		$post['dbIsSet'] = $dbIsSet;
diff --git a/core/templates/installation.php b/core/templates/installation.php
index 25052782e6..fce70cdc3d 100644
--- a/core/templates/installation.php
+++ b/core/templates/installation.php
@@ -54,13 +54,13 @@ script('core', [
 		</p>
 	</fieldset>
 
-	<?php if(!$_['directoryIsSet'] OR !$_['dbIsSet'] OR count($_['errors']) > 0): ?>
+	<?php if(!$_['directoryIsSet'] or !$_['dbIsSet'] or count($_['errors']) > 0): ?>
 	<fieldset id="advancedHeader">
 		<legend><a id="showAdvanced" tabindex="0" href="#"><?php p($l->t( 'Storage & database' )); ?><img src="<?php print_unescaped(image_path('', 'actions/caret-white.svg')); ?>" /></a></legend>
 	</fieldset>
 	<?php endif; ?>
 
-	<?php if(!$_['directoryIsSet'] OR count($_['errors']) > 0): ?>
+	<?php if(!$_['directoryIsSet'] or count($_['errors']) > 0): ?>
 	<fieldset id="datadirField">
 		<div id="datadirContent">
 			<label for="directory"><?php p($l->t( 'Data folder' )); ?></label>
@@ -72,7 +72,7 @@ script('core', [
 	</fieldset>
 	<?php endif; ?>
 
-	<?php if(!$_['dbIsSet'] OR count($_['errors']) > 0): ?>
+	<?php if(!$_['dbIsSet'] or count($_['errors']) > 0): ?>
 	<fieldset id='databaseBackend'>
 		<?php if($_['hasMySQL'] or $_['hasPostgreSQL'] or $_['hasOracle'])
 			$hasOtherDB = true; else $hasOtherDB =false; //other than SQLite ?>
@@ -149,7 +149,7 @@ script('core', [
 		<?php endif; ?>
 	<?php endif; ?>
 
-	<?php if(!$_['dbIsSet'] OR count($_['errors']) > 0): ?>
+	<?php if(!$_['dbIsSet'] or count($_['errors']) > 0): ?>
 		<fieldset id="sqliteInformation" class="warning">
 			<legend><?php p($l->t('Performance warning'));?></legend>
 			<p><?php p($l->t('You chose SQLite as database.'));?></p>
diff --git a/lib/private/ContactsManager.php b/lib/private/ContactsManager.php
index 2913e2b586..6f37ed0fc2 100644
--- a/lib/private/ContactsManager.php
+++ b/lib/private/ContactsManager.php
@@ -146,7 +146,7 @@ namespace OC {
 		 * @return IAddressBook[]
 		 * @since 16.0.0
 		 */
-		public function getUserAddressBooks(): Array {
+		public function getUserAddressBooks(): array {
 			$this->loadAddressBooks();
 			return $this->addressBooks;
 		}
diff --git a/lib/private/Group/Backend.php b/lib/private/Group/Backend.php
index 6c2973542c..4e2f912e7f 100644
--- a/lib/private/Group/Backend.php
+++ b/lib/private/Group/Backend.php
@@ -53,7 +53,7 @@ abstract class Backend implements \OCP\GroupInterface {
 	 */
 	public function getSupportedActions() {
 		$actions = 0;
-		foreach($this->possibleActions AS $action => $methodName) {
+		foreach($this->possibleActions as $action => $methodName) {
 			if(method_exists($this, $methodName)) {
 				$actions |= $action;
 			}
diff --git a/lib/private/Group/Group.php b/lib/private/Group/Group.php
index 38f360b6ce..9eb1b61660 100644
--- a/lib/private/Group/Group.php
+++ b/lib/private/Group/Group.php
@@ -285,7 +285,7 @@ class Group implements IGroup {
 	public function countDisabled() {
 		$users = false;
 		foreach ($this->backends as $backend) {
-			if($backend instanceOf ICountDisabledInGroup) {
+			if($backend instanceof ICountDisabledInGroup) {
 				if($users === false) {
 					//we could directly add to a bool variable, but this would
 					//be ugly
diff --git a/lib/private/Session/CryptoSessionData.php b/lib/private/Session/CryptoSessionData.php
index a0178c7eea..da9bf950ba 100644
--- a/lib/private/Session/CryptoSessionData.php
+++ b/lib/private/Session/CryptoSessionData.php
@@ -50,7 +50,7 @@ class CryptoSessionData implements \ArrayAccess, ISession {
 	protected $sessionValues;
 	/** @var bool */
 	protected $isModified = false;
-	CONST encryptedSessionName = 'encrypted_session_data';
+	const encryptedSessionName = 'encrypted_session_data';
 
 	/**
 	 * @param ISession $session
diff --git a/lib/private/User/Backend.php b/lib/private/User/Backend.php
index 24f7c5161b..53c5a55a2e 100644
--- a/lib/private/User/Backend.php
+++ b/lib/private/User/Backend.php
@@ -68,7 +68,7 @@ abstract class Backend implements UserInterface {
 	 */
 	public function getSupportedActions() {
 		$actions = 0;
-		foreach($this->possibleActions AS $action => $methodName) {
+		foreach($this->possibleActions as $action => $methodName) {
 			if(method_exists($this, $methodName)) {
 				$actions |= $action;
 			}
diff --git a/lib/private/legacy/OC_Helper.php b/lib/private/legacy/OC_Helper.php
index 7cb6e228b5..73154909a4 100644
--- a/lib/private/legacy/OC_Helper.php
+++ b/lib/private/legacy/OC_Helper.php
@@ -367,7 +367,7 @@ class OC_Helper {
 		$it = new RecursiveIteratorIterator($aIt);
 
 		while ($it->valid()) {
-			if (((isset($index) AND ($it->key() == $index)) OR !isset($index)) AND ($it->current() == $needle)) {
+			if (((isset($index) and ($it->key() == $index)) or !isset($index)) and ($it->current() == $needle)) {
 				return $aIt->key();
 			}
 
diff --git a/lib/private/legacy/OC_User.php b/lib/private/legacy/OC_User.php
index d96400ad1d..a9de5cdef9 100644
--- a/lib/private/legacy/OC_User.php
+++ b/lib/private/legacy/OC_User.php
@@ -80,7 +80,7 @@ class OC_User {
 			\OC::$server->getUserManager()->registerBackend($backend);
 		} else {
 			// You'll never know what happens
-			if (null === $backend OR !is_string($backend)) {
+			if (null === $backend or !is_string($backend)) {
 				$backend = 'database';
 			}