diff --git a/lib/CheckQuota.php b/lib/CheckQuota.php
index c13faf6..df4719b 100644
--- a/lib/CheckQuota.php
+++ b/lib/CheckQuota.php
@@ -88,7 +88,7 @@ public function check(string $userId): void {
 
 		$usage = $this->getRelativeQuotaUsage($userId);
 
-		if ($usage > $this->config->getAppValue('quota_warning', 'alert_percentage', 95)) {
+		if ($usage > $this->config->getAppValue('quota_warning', 'alert_percentage', '95')) {
 			if ($this->shouldIssueWarning($userId, 'alert')) {
 				$this->issueWarning($userId, $usage);
 				if ($this->config->getAppValue('quota_warning', 'alert_email', 'no') === 'yes') {
@@ -96,7 +96,7 @@ public function check(string $userId): void {
 				}
 			}
 			$this->updateLastWarning($userId, 'alert');
-		} elseif ($usage > $this->config->getAppValue('quota_warning', 'warning_percentage', 90)) {
+		} elseif ($usage > $this->config->getAppValue('quota_warning', 'warning_percentage', '90')) {
 			if ($this->shouldIssueWarning($userId, 'warning')) {
 				$this->issueWarning($userId, $usage);
 				if ($this->config->getAppValue('quota_warning', 'warning_email', 'no') === 'yes') {
@@ -105,7 +105,7 @@ public function check(string $userId): void {
 			}
 			$this->updateLastWarning($userId, 'warning');
 			$this->removeLastWarning($userId, 'alert');
-		} elseif ($usage > $this->config->getAppValue('quota_warning', 'info_percentage', 85)) {
+		} elseif ($usage > $this->config->getAppValue('quota_warning', 'info_percentage', '85')) {
 			if ($this->shouldIssueWarning($userId, 'info')) {
 				$this->issueWarning($userId, $usage);
 				if ($this->config->getAppValue('quota_warning', 'info_email', 'no') === 'yes') {
@@ -190,7 +190,7 @@ protected function sendEmail(string $userId, float $percentage): void {
 
 		$link = $this->config->getAppValue('quota_warning', 'plan_management_url');
 
-		$help = $l->t('You are using more than %d%% of your storage quota. Try to free up some space by deleting old files you don\'t need anymore.', $percentage);
+		$help = $l->t('You are using more than %d%% of your storage quota. Try to free up some space by deleting old files you don\'t need anymore.', [$percentage]);
 		if ($link !== '') {
 			$emailTemplate->addBodyText(
 				htmlspecialchars($help . ' ' . $l->t('Or click the following button for options to change your data plan.')),
@@ -251,7 +251,7 @@ protected function shouldIssueWarning(string $userId, string $level): bool {
 			return true;
 		}
 
-		$days = (int) $this->config->getAppValue('quota_warning', 'repeat_warning', 7);
+		$days = (int) $this->config->getAppValue('quota_warning', 'repeat_warning', '7');
 
 		if ($days <= 0) {
 			return false;
diff --git a/lib/Notification/Notifier.php b/lib/Notification/Notifier.php
index 7aa7c24..538744c 100644
--- a/lib/Notification/Notifier.php
+++ b/lib/Notification/Notifier.php
@@ -91,14 +91,14 @@ public function prepare(INotification $notification, string $languageCode): INot
 		}
 
 		$usage = $this->checkQuota->getRelativeQuotaUsage($notification->getUser());
-		if ($usage < $this->config->getAppValue('quota_warning', 'info_percentage', 85)) {
+		if ($usage < $this->config->getAppValue('quota_warning', 'info_percentage', '85')) {
 			// User is not in danger zone anymore
 			throw new AlreadyProcessedException();
 		}
 
-		if ($usage > $this->config->getAppValue('quota_warning', 'alert_percentage', 95)) {
+		if ($usage > $this->config->getAppValue('quota_warning', 'alert_percentage', '95')) {
 			$imagePath = $this->url->imagePath(Application::APP_ID, 'app-alert.svg');
-		} elseif ($usage > $this->config->getAppValue('quota_warning', 'warning_percentage', 90)) {
+		} elseif ($usage > $this->config->getAppValue('quota_warning', 'warning_percentage', '90')) {
 			$imagePath = $this->url->imagePath(Application::APP_ID, 'app-warning.svg');
 		} else {
 			$imagePath = $this->url->imagePath(Application::APP_ID, 'app-dark.svg');
diff --git a/lib/Settings.php b/lib/Settings.php
index 0437311..3348a03 100644
--- a/lib/Settings.php
+++ b/lib/Settings.php
@@ -39,14 +39,14 @@ public function __construct(IConfig $config) {
 	public function getForm(): TemplateResponse {
 		$response = new TemplateResponse('quota_warning', 'settings');
 		$response->setParams([
-			'info_percentage' => $this->config->getAppValue('quota_warning', 'info_percentage', 85),
+			'info_percentage' => $this->config->getAppValue('quota_warning', 'info_percentage', '85'),
 			'info_email' => $this->config->getAppValue('quota_warning', 'info_email', 'no') === 'yes',
-			'warning_percentage' => $this->config->getAppValue('quota_warning', 'warning_percentage', 90),
+			'warning_percentage' => $this->config->getAppValue('quota_warning', 'warning_percentage', '90'),
 			'warning_email' => $this->config->getAppValue('quota_warning', 'warning_email', 'no') === 'yes',
-			'alert_percentage' => $this->config->getAppValue('quota_warning', 'alert_percentage', 95),
+			'alert_percentage' => $this->config->getAppValue('quota_warning', 'alert_percentage', '95'),
 			'alert_email' => $this->config->getAppValue('quota_warning', 'alert_email', 'no') === 'yes',
 			'plan_management_url' => $this->config->getAppValue('quota_warning', 'plan_management_url'),
-			'repeat_warning' => $this->config->getAppValue('quota_warning', 'repeat_warning', 7),
+			'repeat_warning' => $this->config->getAppValue('quota_warning', 'repeat_warning', '7'),
 		]);
 
 		return $response;