diff --git a/apps/sharebymail/lib/ShareByMailProvider.php b/apps/sharebymail/lib/ShareByMailProvider.php
index 7c3ad2c42d6d9..ebd4b992fde25 100644
--- a/apps/sharebymail/lib/ShareByMailProvider.php
+++ b/apps/sharebymail/lib/ShareByMailProvider.php
@@ -406,7 +406,7 @@ protected function sendMailNotification($filename,
 		$emailTemplate->addHeading($this->l->t('%1$s shared »%2$s« with you', [$initiatorDisplayName, $filename]), false);
 		$text = $this->l->t('%1$s shared »%2$s« with you.', [$initiatorDisplayName, $filename]);
 		if ($expiration instanceof \DateTime) {
-			$relativeDate = (string)$expiration->diff(new \DateTime('now'))->format("%a");
+			$relativeDate = $expiration->diff(new \DateTime())->format('%a');
 			$text .= ' ' . $this->l->t('It will expire in %1$s days.', [$relativeDate]);
 		}