diff --git a/dist/files_opds-0.6.8.tar.gz b/dist/files_opds-0.6.8.tar.gz
new file mode 100644
index 0000000..4d833ab
Binary files /dev/null and b/dist/files_opds-0.6.8.tar.gz differ
diff --git a/files_opds/appinfo/app.php b/files_opds/appinfo/app.php
index 687488d..6271759 100644
--- a/files_opds/appinfo/app.php
+++ b/files_opds/appinfo/app.php
@@ -2,10 +2,8 @@
 
 $l = OC_L10N::get('files_opds');
 
-require 'files_opds/lib/epub-preview.php';
-
 \OCP\App::registerPersonal('files_opds', 'personal');
 \OCP\App::registerAdmin('files_opds', 'admin');
 
 /* register preview provider */
-\OC::$server->getPreviewManager()->registerProvider('OC\Preview\Epub', array('apps' => array('files_opds')));
+\OC::$server->getPreviewManager()->registerProvider('/application\/epub\+zip/', function() { return new OCA\Files_Opds\EpubPreview; });
diff --git a/files_opds/appinfo/info.xml b/files_opds/appinfo/info.xml
index a2cd3b8..33f07d4 100644
--- a/files_opds/appinfo/info.xml
+++ b/files_opds/appinfo/info.xml
@@ -10,9 +10,9 @@
 		The feed is in compliance with the OPDS 1.1 specification according to the online OPDS validator (http://opds-validator.appspot.com/).
 	</description>
         <licence>AGPL</licence>
-	<version>0.6.7</version>
+	<version>0.6.8</version>
         <author>Frank de Lange</author>
-        <requiremin>7.0</requiremin>
+        <requiremin>8.1</requiremin>
         <shipped>true</shipped>
         <default_enable/>
         <repository type="git">https://github.com/Yetangitu/owncloud-apps</repository>
diff --git a/files_opds/lib/epub-preview.php b/files_opds/lib/epubpreview.php
similarity index 82%
rename from files_opds/lib/epub-preview.php
rename to files_opds/lib/epubpreview.php
index 69e4f8b..eb1231c 100644
--- a/files_opds/lib/epub-preview.php
+++ b/files_opds/lib/epubpreview.php
@@ -10,12 +10,14 @@
  * later.
  */
 
-namespace OC\Preview;
+namespace OCA\Files_Opds;
+
+use OCP\Preview\IProvider;
 
 /**
  * Epub preview - returns cover or null
  */
-class Epub extends Provider {
+class EpubPreview implements IProvider {
 
         public function getMimeType() {
                 return '/application\/epub\+zip/';
@@ -43,5 +45,8 @@ class Epub extends Provider {
 		return (($cover !== null) && $image->valid()) ? $image : false;
         }
 
+	public function isAvailable(\OCP\Files\FileInfo $file) {
+		return $file->getSize() > 0;
+	}
 }