diff --git a/src/acdhOeaw/arche/lib/ingest/Indexer.php b/src/acdhOeaw/arche/lib/ingest/Indexer.php
index 47df8e1..6fc5c5e 100644
--- a/src/acdhOeaw/arche/lib/ingest/Indexer.php
+++ b/src/acdhOeaw/arche/lib/ingest/Indexer.php
@@ -599,7 +599,7 @@ private function indexEntry(DirectoryIterator $i) {
             $location = self::getRelPath(self::sanitizePath($i->getPathname()), $this->containerDir);
             $id       = $this->containerToUriPrefix . str_replace('%2F', '/', rawurlencode($location));
             $class    = $i->isDir() ? $this->collectionClass : $this->binaryClass;
-            $parent   = $this->parent === null ? null : $this->parent->getUri();
+            $parent   = isset($this->parent) ? $this->parent->getUri() : null;
             $file     = new File($this->repo, $id, $i->getPathname(), $location, $class, $parent);
             if ($this->metaLookup !== null) {
                 $file->setMetaLookup($this->metaLookup, $this->metaLookupRequire);
diff --git a/src/acdhOeaw/arche/lib/ingest/schema/File.php b/src/acdhOeaw/arche/lib/ingest/schema/File.php
index 2484777..b188484 100644
--- a/src/acdhOeaw/arche/lib/ingest/schema/File.php
+++ b/src/acdhOeaw/arche/lib/ingest/schema/File.php
@@ -42,6 +42,9 @@
  */
 class File extends SchemaObject {
 
+    const GUZZLE_PSR7_V1_MIME_FUNC = '\GuzzleHttp\Psr7\mimetype_from_filename';
+    const GUZZLE_PSR7_V2_MIME_FUNC = '\GuzzleHttp\Psr7\MimeType::fromFilename';
+
     /**
      * File path
      * @var string 
@@ -170,7 +173,8 @@ public function setMetaLookup(MetaLookupInterface $metaLookup,
      * @return string
      */
     public function getMime(): ?string {
-        $mime = \GuzzleHttp\Psr7\mimetype_from_filename(basename($this->path));
+        $f    = function_exists(self::GUZZLE_PSR7_V1_MIME_FUNC) ? self::GUZZLE_PSR7_V1_MIME_FUNC : self::GUZZLE_PSR7_V2_MIME_FUNC;
+        $mime = $f(basename($this->path));
         if ($mime === null) {
             $mime = mime_content_type($this->path);
         }