@@ -90,7 +90,8 @@ public function initialize(\Sabre\DAV\Server $server) {
 	public function logException(\Exception $ex) {
 		$exceptionClass = get_class($ex);
 		$level = \OCP\Util::FATAL;
-		if (isset($this->nonFatalExceptions[$exceptionClass])) {
+		if (isset($this->nonFatalExceptions[$exceptionClass]) ||
+			($exceptionClass === 'Sabre\DAV\Exception\ServiceUnavailable' && $ex->getMessage() === 'System in maintenance mode.')) {
 			$level = \OCP\Util::DEBUG;
 		}
 
 
@@ -28,6 +28,7 @@
 use OC\Log;
 use PHPUnit_Framework_MockObject_MockObject;
 use Sabre\DAV\Exception\NotFound;
+use Sabre\DAV\Exception\ServiceUnavailable;
 use Sabre\DAV\Server;
 use Test\TestCase;
 
@@ -77,6 +78,8 @@ public function testLogging($expectedLogLevel, $expectedMessage, $exception) {
 	public function providesExceptions() {
 		return [
 			[0, '', new NotFound()],
+			[0, 'System in maintenance mode.', new ServiceUnavailable('System in maintenance mode.')],
+			[4, 'Upgrade needed', new InvalidPath('Upgrade needed')],
 			[4, 'This path leads to nowhere', new InvalidPath('This path leads to nowhere')]
 		];
 	}
Original file line number	Diff line number	Diff line change
`@@ -90,7 +90,8 @@ public function initialize(\Sabre\DAV\Server $server) {`
`90`	`90`	`public function logException(\Exception $ex) {`
`91`	`91`	`$exceptionClass = get_class($ex);`
`92`	`92`	`$level = \OCP\Util::FATAL;`
`93`		`- if (isset($this->nonFatalExceptions[$exceptionClass])) {`
	`93`	`+ if (isset($this->nonFatalExceptions[$exceptionClass]) \|\|`
	`94`	`+ ($exceptionClass === 'Sabre\DAV\Exception\ServiceUnavailable' && $ex->getMessage() === 'System in maintenance mode.')) {`
`94`	`95`	`$level = \OCP\Util::DEBUG;`
`95`	`96`	`}`
`96`	`97`