diff --git a/apps/dav/lib/CardDAV/ImageExportPlugin.php b/apps/dav/lib/CardDAV/ImageExportPlugin.php
index e4b1047173de7..5bcbf80c94c5b 100644
--- a/apps/dav/lib/CardDAV/ImageExportPlugin.php
+++ b/apps/dav/lib/CardDAV/ImageExportPlugin.php
@@ -15,6 +15,7 @@
 use Sabre\HTTP\RequestInterface;
 use Sabre\HTTP\ResponseInterface;
 use Symfony\Component\HttpFoundation\HeaderUtils;
+use Symfony\Component\String\UnicodeString;
 
 class ImageExportPlugin extends ServerPlugin {
 
@@ -88,9 +89,7 @@ public function httpGet(RequestInterface $request, ResponseInterface $response)
 			$response->setHeader('Content-Type', $file->getMimeType());
 			$fileName = $node->getName() . '.' . PhotoCache::ALLOWED_CONTENT_TYPES[$file->getMimeType()];
 			$sanitized = str_replace(['/', '\\'], '-', $fileName);
-			$fallback = @iconv('UTF-8', 'ASCII//TRANSLIT', $sanitized) ?: $sanitized;
-			$fallback = preg_replace('/[^\x20-\x7e]/', '', $fallback);
-			$fallback = str_replace('%', '', $fallback);
+			$fallback = str_replace('%', '', (new UnicodeString($sanitized))->ascii()->toString());
 			$response->setHeader('Content-Disposition', HeaderUtils::makeDisposition(HeaderUtils::DISPOSITION_ATTACHMENT, $sanitized, $fallback));
 			$response->setStatus(Http::STATUS_OK);
 
diff --git a/apps/dav/lib/Provisioning/Apple/AppleProvisioningPlugin.php b/apps/dav/lib/Provisioning/Apple/AppleProvisioningPlugin.php
index 8796db84f5836..59a33a31f9e39 100644
--- a/apps/dav/lib/Provisioning/Apple/AppleProvisioningPlugin.php
+++ b/apps/dav/lib/Provisioning/Apple/AppleProvisioningPlugin.php
@@ -16,6 +16,7 @@
 use Sabre\HTTP\RequestInterface;
 use Sabre\HTTP\ResponseInterface;
 use Symfony\Component\HttpFoundation\HeaderUtils;
+use Symfony\Component\String\UnicodeString;
 
 class AppleProvisioningPlugin extends ServerPlugin {
 	/**
@@ -129,9 +130,7 @@ public function httpGet(RequestInterface $request, ResponseInterface $response):
 
 		$response->setStatus(Http::STATUS_OK);
 		$sanitized = str_replace(['/', '\\'], '-', $filename);
-		$fallback = @iconv('UTF-8', 'ASCII//TRANSLIT', $sanitized) ?: $sanitized;
-		$fallback = preg_replace('/[^\x20-\x7e]/', '', $fallback);
-		$fallback = str_replace('%', '', $fallback);
+		$fallback = str_replace('%', '', (new UnicodeString($sanitized))->ascii()->toString());
 		$response->setHeader('Content-Disposition', HeaderUtils::makeDisposition(HeaderUtils::DISPOSITION_ATTACHMENT, $sanitized, $fallback));
 		$response->setHeader('Content-Type', 'application/xml; charset=utf-8');
 		$response->setBody($body);
diff --git a/lib/public/AppFramework/Http/DownloadResponse.php b/lib/public/AppFramework/Http/DownloadResponse.php
index 6f3a3660ce11a..f80bc0cc371fc 100644
--- a/lib/public/AppFramework/Http/DownloadResponse.php
+++ b/lib/public/AppFramework/Http/DownloadResponse.php
@@ -9,6 +9,7 @@
 
 use OCP\AppFramework\Http;
 use Symfony\Component\HttpFoundation\HeaderUtils;
+use Symfony\Component\String\UnicodeString;
 
 /**
  * Prompts the user to download the a file
@@ -31,9 +32,7 @@ public function __construct(string $filename, string $contentType, int $status =
 		parent::__construct($status, $headers);
 
 		$sanitized = str_replace(['/', '\\'], '-', $filename);
-		$fallback = @iconv('UTF-8', 'ASCII//TRANSLIT', $sanitized) ?: $sanitized;
-		$fallback = preg_replace('/[^\x20-\x7e]/', '', $fallback);
-		$fallback = str_replace('%', '', $fallback);
+		$fallback = str_replace('%', '', (new UnicodeString($sanitized))->ascii()->toString());
 		$this->addHeader('Content-Disposition', HeaderUtils::makeDisposition(HeaderUtils::DISPOSITION_ATTACHMENT, $sanitized, $fallback));
 		$this->addHeader('Content-Type', $contentType);
 	}