diff --git a/h5p-development.class.php b/h5p-development.class.php
index d599ca1..75e9daf 100644
--- a/h5p-development.class.php
+++ b/h5p-development.class.php
@@ -30,7 +30,7 @@ class H5PDevelopment {
       $this->findLibraries($filesPath . '/development');
     }
   }
-  
+
   /**
    * Get contents of file.
    *
@@ -41,15 +41,15 @@ class H5PDevelopment {
     if (file_exists($file) === FALSE) {
       return NULL;
     }
-    
+
     $contents = file_get_contents($file);
     if ($contents === FALSE) {
       return NULL;
     }
-    
+
     return $contents;
   }
-  
+
   /**
    * Scans development directory and find all libraries.
    *
@@ -57,39 +57,39 @@ class H5PDevelopment {
    */
   private function findLibraries($path) {
     $this->libraries = array();
-    
+
     if (is_dir($path) === FALSE) {
-      return; 
+      return;
     }
-    
+
     $contents = scandir($path);
-    
+
     for ($i = 0, $s = count($contents); $i < $s; $i++) {
       if ($contents[$i]{0} === '.') {
         continue; // Skip hidden stuff.
       }
-      
+
       $libraryPath = $path . '/' . $contents[$i];
       $libraryJSON = $this->getFileContents($libraryPath . '/library.json');
       if ($libraryJSON === NULL) {
         continue; // No JSON file, skip.
       }
-      
+
       $library = json_decode($libraryJSON, TRUE);
       if ($library === FALSE) {
         continue; // Invalid JSON.
       }
-      
+
       // TODO: Validate props? Not really needed, is it? this is a dev site.
-      
+
       // Save/update library.
       $library['libraryId'] = $this->h5pF->getLibraryId($library['machineName'], $library['majorVersion'], $library['minorVersion']);
       $this->h5pF->saveLibraryData($library, $library['libraryId'] === FALSE);
-      
+
       $library['path'] = $libraryPath;
       $this->libraries[H5PDevelopment::libraryToString($library['machineName'], $library['majorVersion'], $library['minorVersion'])] = $library;
     }
-    
+
     // TODO: Should we remove libraries without files? Not really needed, but must be cleaned up some time, right?
 
     // Go trough libraries and insert dependencies. Missing deps. will just be ignored and not available. (I guess?!)
@@ -106,17 +106,17 @@ class H5PDevelopment {
     }
     // TODO: Deps must be inserted into h5p_nodes_libraries as well... ? But only if they are used?!
   }
-  
+
   /**
    * @return array Libraris in development folder.
    */
   public function getLibraries() {
     return $this->libraries;
   }
-  
+
   /**
    * Get library
-   * 
+   *
    * @param string $name of the library.
    * @param int $majorVersion of the library.
    * @param int $minorVersion of the library.
@@ -126,10 +126,10 @@ class H5PDevelopment {
     $library = H5PDevelopment::libraryToString($name, $majorVersion, $minorVersion);
     return isset($this->libraries[$library]) === TRUE ? $this->libraries[$library] : NULL;
   }
-  
+
   /**
    * Get semantics for the given library.
-   * 
+   *
    * @param string $name of the library.
    * @param int $majorVersion of the library.
    * @param int $minorVersion of the library.
@@ -137,32 +137,32 @@ class H5PDevelopment {
    */
   public function getSemantics($name, $majorVersion, $minorVersion) {
     $library = H5PDevelopment::libraryToString($name, $majorVersion, $minorVersion);
-    
+
     if (isset($this->libraries[$library]) === FALSE) {
       return NULL;
     }
-    
+
     return $this->getFileContents($this->libraries[$library]['path'] . '/semantics.json');
   }
-  
+
   /**
    * Get translations for the given library.
-   * 
+   *
    * @param string $name of the library.
    * @param int $majorVersion of the library.
    * @param int $minorVersion of the library.
    * @return string Translation
    */
-  public function getLanguage($name, $majorVersion, $minorVersion) {
+  public function getLanguage($name, $majorVersion, $minorVersion, $language) {
     $library = H5PDevelopment::libraryToString($name, $majorVersion, $minorVersion);
-    
+
     if (isset($this->libraries[$library]) === FALSE) {
       return NULL;
     }
-    
-    return $this->getFileContents($this->libraries[$library]['path'] . '/language/' . $this->language . '.json');
+
+    return $this->getFileContents($this->libraries[$library]['path'] . '/language/' . $language . '.json');
   }
-  
+
   /**
    * Writes library as string on the form "name majorVersion.minorVersion"
    *
@@ -175,4 +175,3 @@ class H5PDevelopment {
     return $name . ' ' . $majorVersion . '.' . $minorVersion;
   }
 }
-
diff --git a/h5p.classes.php b/h5p.classes.php
index 3cc31ac..a6de0d4 100644
--- a/h5p.classes.php
+++ b/h5p.classes.php
@@ -55,31 +55,31 @@ interface H5PFrameworkInterface {
    * @return string Path to the last uploaded h5p
    */
   public function getUploadedH5pPath();
-  
+
   /**
    * Get the list of the current installed libraries
-   * 
+   *
    * @return array Associative array containg one item per machine name. This item contains an array of libraries.
    */
   public function loadLibraries();
-  
+
   /**
    * Saving the unsupported library list
-   * 
+   *
    * @param array A list of unsupported libraries
    */
   public function setUnsupportedLibraries($libraries);
-  
+
   /**
    * Returns unsupported libraries
-   * 
+   *
    * @return array A list of the unsupported libraries
    */
   public function getUnsupportedLibraries();
-  
+
   /**
    * Returns the URL to the library admin page
-   * 
+   *
    * @return string URL to admin page
    */
   public function getAdminUrl();
@@ -108,7 +108,7 @@ interface H5PFrameworkInterface {
    * @param string $defaultLibraryWhitelist
    */
   public function getWhitelist($isLibrary, $defaultContentWhitelist, $defaultLibraryWhitelist);
-  
+
   /**
    * Is the library a patched version of an existing library?
    *
@@ -147,23 +147,23 @@ interface H5PFrameworkInterface {
    *  Object holding the information that is to be stored
    */
   public function saveLibraryData(&$libraryData, $new = TRUE);
-  
+
   /**
    * Insert new content.
-   * 
+   *
    * @param object $content
    * @param int $contentMainId
    */
   public function insertContent($content, $contentMainId = NULL);
-  
+
   /**
    * Update old content.
-   * 
+   *
    * @param object $content
    * @param int $contentMainId
    */
   public function updateContent($content, $contentMainId = NULL);
-  
+
   /**
    * Save what libraries a library is dependending on
    *
@@ -219,11 +219,11 @@ interface H5PFrameworkInterface {
   public function saveLibraryUsage($contentId, $librariesInUse);
 
   /**
-   * Get number of content/nodes using a library, and the number of 
+   * Get number of content/nodes using a library, and the number of
    * dependencies to other libraries
-   * 
+   *
    * @param int $library_id
-   * @return array The array contains two elements, keyed by 'content' and 'libraries'. 
+   * @return array The array contains two elements, keyed by 'content' and 'libraries'.
    *               Each element contains a number
    */
   public function getLibraryUsage($libraryId);
@@ -249,7 +249,7 @@ interface H5PFrameworkInterface {
    * @return string semantics.
    */
   public function loadLibrarySemantics($name, $majorVersion, $minorVersion);
-  
+
   /**
    * Makes it possible to alter the semantics, adding custom fields, etc.
    *
@@ -267,21 +267,21 @@ interface H5PFrameworkInterface {
    *  Library Id
    */
   public function deleteLibraryDependencies($libraryId);
-  
+
   /**
    * Delete a library from database and file system
-   * 
+   *
    * @param mixed $library Library
    */
   public function deleteLibrary($library);
-  
+
   /**
    * Load content.
    *
    * @return object Content, null if not found.
    */
   public function loadContent($id);
-  
+
   /**
    * Load dependencies for the given content of the given type.
    *
@@ -290,49 +290,55 @@ interface H5PFrameworkInterface {
    * @return array
    */
   public function loadContentDependencies($id, $type = NULL);
-  
+
   /**
-   * Get data from cache.
-   * 
-   * @param string $group
-   * @param string $key
+   * Get stored setting.
+   *
+   * @param string $name Identifier
+   * @param string $default Optional
+   * @return mixed data
    */
-  public function cacheGet($group, $key);
-  
+  public function getOption($name, $default = NULL);
+
   /**
-   * Store data in cache.
-   * 
-   * @param string $group
-   * @param string $key
-   * @param mixed $data
+   * Stores the given setting.
+   * For example when did we last check h5p.org for updates to our libraries.
+   *
+   * @param string $name Identifier
+   * @param mixed $value Data
    */
-  public function cacheSet($group, $key, $data);
-  
+  public function setOption($name, $value);
+
   /**
-   * Delete data from cache.
-   * 
-   * @param string $group
-   * @param string $key
+   * This will set the filtered parameters for the given content.
+   *
+   * @param int $content_id
+   * @param string $parameters filtered
    */
-  public function cacheDel($group, $key = NULL);
-  
+  public function setFilteredParameters($content_id, $parameters = '');
+
   /**
-   * Will invalidate the cache for the content that uses the specified library.
-   * This means that the content dependencies has to be rebuilt, and the parameters refiltered.
-   * 
+   * Will clear filtered params for all the content that uses the specified
+   * library. This means that the content dependencies will have to be rebuilt,
+   * and the parameters refiltered.
+   *
    * @param int $library_id
    */
-  public function invalidateContentCache($library_id);
-  
+  public function clearFilteredParameters($library_id);
+
   /**
-   * Get content without cache.
+   * Get number of contents that has to get their content dependencies rebuilt
+   * and parameters refiltered.
+   *
+   * @return int
    */
-  public function getNotCached();
-  
+  public function getNumNotFiltered();
+
   /**
    * Get number of contents using library as main library.
-   * 
+   *
    * @param int $library_id
+   * @return int
    */
   public function getNumContent($library_id);
 }
@@ -447,14 +453,14 @@ class H5PValidator {
 
     // Extract and then remove the package file.
     $zip = new ZipArchive;
-    
+
     // Only allow files with the .h5p extension:
     if (strtolower(substr($tmpPath, -3)) !== 'h5p') {
       $this->h5pF->setErrorMessage($this->h5pF->t('The file you uploaded is not a valid HTML5 Package (It does not have the .h5p file extension)'));
       H5PCore::deleteFileTree($tmpDir);
       return;
     }
-    
+
     if ($zip->open($tmpPath) === true) {
       $zip->extractTo($tmpDir);
       $zip->close();
@@ -482,7 +488,7 @@ class H5PValidator {
         if ($skipContent === TRUE) {
           continue;
         }
-      
+
         $mainH5pData = $this->getJsonData($filePath);
         if ($mainH5pData === FALSE) {
           $valid = FALSE;
@@ -540,7 +546,7 @@ class H5PValidator {
         }
 
         $libraryH5PData = $this->getLibraryData($file, $filePath, $tmpDir);
-        
+
         if ($libraryH5PData !== FALSE) {
           // Library's directory name must be:
           // - <machineName>
@@ -576,7 +582,7 @@ class H5PValidator {
     }
     if ($valid) {
       if ($upgradeOnly) {
-        // When upgrading, we opnly add allready installed libraries, 
+        // When upgrading, we opnly add allready installed libraries,
         // and new dependent libraries
         $upgrades = array();
         foreach ($libraries as &$library) {
@@ -594,25 +600,25 @@ class H5PValidator {
             }
           }
         }
-        
+
         $libraries = $upgrades;
       }
-      
+
       $this->h5pC->librariesJsonData = $libraries;
-      
+
       if ($skipContent === FALSE) {
         $this->h5pC->mainJsonData = $mainH5pData;
         $this->h5pC->contentJsonData = $contentJsonData;
         $libraries['mainH5pData'] = $mainH5pData; // Check for the dependencies in h5p.json as well as in the libraries
       }
-      
+
       $missingLibraries = $this->getMissingLibraries($libraries);
       foreach ($missingLibraries as $missing) {
         if ($this->h5pF->getLibraryId($missing['machineName'], $missing['majorVersion'], $missing['minorVersion'])) {
           unset($missingLibraries[H5PCore::libraryToString($missing)]);
         }
       }
-      
+
       if (!empty($missingLibraries)) {
         foreach ($missingLibraries as $library) {
           $this->h5pF->setErrorMessage($this->h5pF->t('Missing required library @library', array('@library' => H5PCore::libraryToString($library))));
@@ -1021,7 +1027,7 @@ class H5PStorage {
 
   public $h5pF;
   public $h5pC;
-  
+
   public $contentId = NULL; // Quick fix so WP can get ID of new content.
 
   /**
@@ -1052,11 +1058,11 @@ class H5PStorage {
     $library_saved = FALSE;
     $upgradedLibsCount = 0;
     $mayUpdateLibraries = $this->h5pF->mayUpdateLibraries();
-    
+
     foreach ($this->h5pC->librariesJsonData as &$library) {
       $libraryId = $this->h5pF->getLibraryId($library['machineName'], $library['majorVersion'], $library['minorVersion']);
       $library['saveDependencies'] = TRUE;
-      
+
       if (!$libraryId) {
         $new = TRUE;
       }
@@ -1101,21 +1107,21 @@ class H5PStorage {
         if (isset($library['editorDependencies'])) {
           $this->h5pF->saveLibraryDependencies($library['libraryId'], $library['editorDependencies'], 'editor');
         }
-        
+
         // Make sure libraries dependencies, parameter filtering and export files gets regenerated for all content who uses this library.
-        $this->h5pF->invalidateContentCache($library['libraryId']);
-        
+        $this->h5pF->clearFilteredParameters($library['libraryId']);
+
         $upgradedLibsCount++;
       }
     }
-    
+
     if (!$skipContent) {
       $current_path = $this->h5pF->getUploadedH5pFolderPath() . DIRECTORY_SEPARATOR . 'content';
-      
+
       // Find out which libraries are used by this package/content
       $librariesInUse = array();
       $this->h5pC->findLibraryDependencies($librariesInUse, $this->h5pC->mainJsonData);
-      
+
       // Save content
       if ($content === NULL) {
         $content = array();
@@ -1132,19 +1138,19 @@ class H5PStorage {
       if (!is_dir($contents_path)) {
         mkdir($contents_path, 0777, true);
       }
-      
+
       // Move the content folder
       $destination_path = $contents_path . DIRECTORY_SEPARATOR . $contentId;
       @rename($current_path, $destination_path);
-      
+
       // Save the content library dependencies
       $this->h5pF->saveLibraryUsage($contentId, $librariesInUse);
       H5PCore::deleteFileTree($this->h5pF->getUploadedH5pFolderPath());
     }
-    
+
     // Update supported library list if neccessary:
     $this->h5pC->validateLibrarySupport(TRUE);
-    
+
     if ($upgradeOnly) {
       // TODO - support translation
       $this->h5pF->setInfoMessage($this->h5pF->t('@num libraries were upgraded!', array('@num' => $upgradedLibsCount)));
@@ -1152,7 +1158,7 @@ class H5PStorage {
 
     return $library_saved;
   }
-  
+
   /**
    * Delete an H5P package
    *
@@ -1221,7 +1227,7 @@ Class H5PExport {
     $this->h5pF = $H5PFramework;
     $this->h5pC = $H5PCore;
   }
-  
+
   /**
    * Return path to h5p package.
    *
@@ -1234,7 +1240,7 @@ Class H5PExport {
     $h5pDir = $this->h5pF->getH5pPath() . DIRECTORY_SEPARATOR;
     $tempPath = $h5pDir . 'temp' . DIRECTORY_SEPARATOR . $content['id'];
     $zipPath = $h5pDir . 'exports' . DIRECTORY_SEPARATOR . $content['id'] . '.h5p';
-    
+
     // Temp dir to put the h5p files in
     @mkdir($tempPath, 0777, TRUE);
     @mkdir($h5pDir . 'exports', 0777, TRUE);
@@ -1251,8 +1257,8 @@ Class H5PExport {
     // Build h5p.json
     $h5pJson = array (
       'title' => $content['title'],
-      // TODO - stop using 'und', this is not the preferred way. 
-      // Either remove language from the json if not existing, or use "language": null 
+      // TODO - stop using 'und', this is not the preferred way.
+      // Either remove language from the json if not existing, or use "language": null
       'language' => isset($content['language']) ? $content['language'] : 'und',
       'mainLibrary' => $content['library']['name'],
       'embedTypes' => $embedTypes,
@@ -1261,7 +1267,7 @@ Class H5PExport {
     // Add dependencies to h5p
     foreach ($content['dependencies'] as $dependency) {
       $library = $dependency['library'];
-      
+
       // Copy library to h5p
       $source = isset($library['path']) ? $library['path'] : $h5pDir . 'libraries' . DIRECTORY_SEPARATOR . H5PCore::libraryToString($library, TRUE);
       $destination = $tempPath . DIRECTORY_SEPARATOR . $library['machineName'];
@@ -1269,7 +1275,7 @@ Class H5PExport {
 
       // Do not add editor dependencies to h5p json.
       if ($dependency['type'] === 'editor') {
-        continue; 
+        continue;
       }
 
       $h5pJson[$dependency['type'] . 'Dependencies'][] = array(
@@ -1333,7 +1339,7 @@ Class H5PExport {
    */
   private function addEditorLibraries($libraries, $editorLibraries) {
     foreach ($editorLibraries as $editorLibrary) {
-      $libraries[$editorLibrary['machineName']] = $editorLibrary;      
+      $libraries[$editorLibrary['machineName']] = $editorLibrary;
     }
     return $libraries;
   }
@@ -1378,12 +1384,12 @@ class H5PCore {
    */
   public function __construct($H5PFramework, $path, $language = 'en', $export = FALSE, $development_mode = H5PDevelopment::MODE_NONE) {
     $this->h5pF = $H5PFramework;
-    
+
     $this->h5pF = $H5PFramework;
     $this->path = $path;
     $this->exportEnabled = $export;
     $this->development_mode = $development_mode;
-    
+
     if ($development_mode & H5PDevelopment::MODE_LIBRARY) {
       $this->h5pD = new H5PDevelopment($this->h5pF, $path, $language);
     }
@@ -1391,7 +1397,7 @@ class H5PCore {
 
   /**
    * Save content and clear cache.
-   * 
+   *
    * @param array $content
    * @return int Content ID
    */
@@ -1400,17 +1406,12 @@ class H5PCore {
       $this->h5pF->updateContent($content, $contentMainId);
     }
     else {
-      $content['id'] = $this->h5pF->insertContent($content, $contentMainId); 
+      $content['id'] = $this->h5pF->insertContent($content, $contentMainId);
     }
-    
-    if (!isset($content['filtered'])) {
-      // TODO: Add filtered to all impl. and remove
-      $this->h5pF->cacheDel('parameters', $content['id']);
-    }
-    
+
     return $content['id'];
   }
-  
+
   /**
    * Load content.
    *
@@ -1419,7 +1420,7 @@ class H5PCore {
    */
   public function loadContent($id) {
     $content = $this->h5pF->loadContent($id);
-    
+
     if ($content !== NULL) {
       $content['library'] = array(
         'id' => $content['libraryId'],
@@ -1430,7 +1431,7 @@ class H5PCore {
         'fullscreen' => $content['libraryFullscreen'],
       );
       unset($content['libraryId'], $content['libraryName'], $content['libraryEmbedTypes'], $content['libraryFullscreen']);
-      
+
 //      // TODO: Move to filterParameters?
 //      if ($this->development_mode & H5PDevelopment::MODE_CONTENT) {
 //        // TODO: Remove Drupal specific stuff
@@ -1444,29 +1445,21 @@ class H5PCore {
 //        }
 //      }
     }
-    
+
     return $content;
   }
-  
+
   /**
    * Filter content run parameters, rebuild content dependecy cache and export file.
-   * 
+   *
    * @param Object $content
    * @return Object NULL on failure.
    */
   public function filterParameters($content) {
-    if (isset($content['filtered'])) {
-      $params = ($content['filtered'] === '' ? NULL : $content['filtered']);
-    }
-    else {
-      // TODO: Add filtered to all impl. and remove
-      $params = $this->h5pF->cacheGet('parameters', $content['id']);
+    if (isset($content['filtered']) && $content['filtered'] !== '') {
+      return $content['filtered'];
     }
 
-    if ($params !== NULL) {
-      return $params;
-    }
-    
     // Validate and filter against main library semantics.
     $validator = new H5PContentValidator($this->h5pF, $this);
     $params = (object) array(
@@ -1476,25 +1469,25 @@ class H5PCore {
     $validator->validateLibrary($params, (object) array('options' => array($params->library)));
 
     $params = json_encode($params->params);
-  
+
     // Update content dependencies.
     $content['dependencies'] = $validator->getDependencies();
     $this->h5pF->deleteLibraryUsage($content['id']);
     $this->h5pF->saveLibraryUsage($content['id'], $content['dependencies']);
-    
+
     if ($this->exportEnabled) {
       // Recreate export file
       $exporter = new H5PExport($this->h5pF, $this);
       $exporter->createExportFile($content);
-      
+
       // TODO: Should we rather create the file once first accessed, like imagecache?
     }
 
     // Cache.
-    $this->h5pF->cacheSet('parameters', $content['id'], $params);
+    $this->h5pF->setFilteredParameters($content['id'], $params);
     return $params;
   }
-  
+
   /**
    * Find the files required for this content to work.
    *
@@ -1503,10 +1496,10 @@ class H5PCore {
    */
   public function loadContentDependencies($id, $type = NULL) {
     $dependencies = $this->h5pF->loadContentDependencies($id, $type);
-  
+
     if ($this->development_mode & H5PDevelopment::MODE_LIBRARY) {
       $developmentLibraries = $this->h5pD->getLibraries();
-      
+
       foreach ($dependencies as $key => $dependency) {
         $libraryString = H5PCore::libraryToString($dependency);
         if (isset($developmentLibraries[$libraryString])) {
@@ -1515,13 +1508,13 @@ class H5PCore {
         }
       }
     }
-    
+
     return $dependencies;
   }
-  
+
   /**
    * Get all dependency assets of the given type
-   * 
+   *
    * @param array $dependency
    * @param string $type
    * @param array $assets
@@ -1531,12 +1524,12 @@ class H5PCore {
     if (empty($dependency[$type]) || $dependency[$type][0] === '') {
       return;
     }
-    
+
     // Check if we should skip CSS.
     if ($type === 'preloadedCss' && (isset($dependency['dropCss']) && $dependency['dropCss'] === '1')) {
       return;
     }
-    
+
     foreach ($dependency[$type] as $file) {
       $assets[] = (object) array(
         'path' => $dependency['path'] . '/' . trim(is_array($file) ? $file['path'] : $file),
@@ -1544,23 +1537,23 @@ class H5PCore {
       );
     }
   }
-  
+
   /**
    * Combines path with cache buster / version.
-   * 
+   *
    * @param array $assets
    * @return array
    */
   public function getAssetsUrls($assets) {
     $urls = array();
-    
+
     foreach ($assets as $asset) {
       $urls[] = $asset->path . $asset->version;
     }
-    
+
     return $urls;
   }
-  
+
   /**
    * Return file paths for all dependecies files.
    *
@@ -1578,14 +1571,14 @@ class H5PCore {
         $dependency['preloadedJs'] = explode(',', $dependency['preloadedJs']);
         $dependency['preloadedCss'] = explode(',', $dependency['preloadedCss']);
       }
-      
+
       $dependency['version'] = "?ver={$dependency['majorVersion']}.{$dependency['minorVersion']}.{$dependency['patchVersion']}";
       $this->getDependencyAssets($dependency, 'preloadedJs', $files['scripts']);
       $this->getDependencyAssets($dependency, 'preloadedCss', $files['styles']);
     }
     return $files;
   }
-  
+
   /**
    * Load library semantics.
    *
@@ -1597,20 +1590,20 @@ class H5PCore {
       // Try to load from dev lib
       $semantics = $this->h5pD->getSemantics($name, $majorVersion, $minorVersion);
     }
-    
+
     if ($semantics === NULL) {
       // Try to load from DB.
       $semantics = $this->h5pF->loadLibrarySemantics($name, $majorVersion, $minorVersion);
     }
-    
+
     if ($semantics !== NULL) {
       $semantics = json_decode($semantics);
       $this->h5pF->alterLibrarySemantics($semantics, $name, $majorVersion, $minorVersion);
     }
-    
+
     return $semantics;
   }
-  
+
   /**
    * Load library.
    *
@@ -1625,31 +1618,31 @@ class H5PCore {
         $library['semantics'] = $this->h5pD->getSemantics($name, $majorVersion, $minorVersion);
       }
     }
-    
+
     if ($library === NULL) {
       // Try to load from DB.
       $library = $this->h5pF->loadLibrary($name, $majorVersion, $minorVersion);
     }
-  
+
     return $library;
   }
-  
+
   /**
    * Deletes a library
-   * 
+   *
    * @param unknown $libraryId
    */
   public function deleteLibrary($libraryId) {
     $this->h5pF->deleteLibrary($libraryId);
-    
+
     // Force update of unsupported libraries list:
     $this->validateLibrarySupport(TRUE);
   }
-  
+
   /**
-   * Recursive. Goes through the dependency tree for the given library and 
+   * Recursive. Goes through the dependency tree for the given library and
    * adds all the dependencies to the given array in a flat format.
-   * 
+   *
    * @param array $librariesUsed Flat list of all dependencies.
    * @param array $library To find all dependencies for.
    * @param bool $editor Used interally to force all preloaded sub dependencies of an editor dependecy to be editor dependencies.
@@ -1660,18 +1653,18 @@ class H5PCore {
       if (!isset($library[$property])) {
         continue; // Skip, no such dependencies.
       }
-      
+
       if ($type === 'preloaded' && $editor === TRUE) {
         // All preloaded dependencies of an editor library is set to editor.
         $type = 'editor';
       }
-      
+
       foreach ($library[$property] as $dependency) {
         $dependencyKey = $type . '-' . $dependency['machineName'];
         if (isset($dependencies[$dependencyKey]) === TRUE) {
           continue; // Skip, already have this.
         }
-        
+
         $dependencyLibrary = $this->loadLibrary($dependency['machineName'], $dependency['majorVersion'], $dependency['minorVersion']);
         if ($dependencyLibrary) {
           $dependencies[$dependencyKey] = array(
@@ -1800,7 +1793,7 @@ class H5PCore {
     }
     return FALSE;
   }
-  
+
   /**
    * Determine the correct embed type to use.
    *
@@ -1809,32 +1802,32 @@ class H5PCore {
   public static function determineEmbedType($contentEmbedType, $libraryEmbedTypes) {
     // Detect content embed type
     $embedType = strpos(strtolower($contentEmbedType), 'div') !== FALSE ? 'div' : 'iframe';
-    
+
     if ($libraryEmbedTypes !== NULL && $libraryEmbedTypes !== '') {
       // Check that embed type is available for library
       $embedTypes = strtolower($libraryEmbedTypes);
       if (strpos($embedTypes, $embedType) === FALSE) {
         // Not available, pick default.
         $embedType = strpos($embedTypes, 'div') !== FALSE ? 'div' : 'iframe';
-      }  
+      }
     }
-    
+
     return $embedType;
   }
-  
+
   /**
    * Get the absolute version for the library as a human readable string.
-   * 
+   *
    * @param object $library
    * @return string
    */
   public static function libraryVersion($library) {
     return $library->major_version . '.' . $library->minor_version . '.' . $library->patch_version;
   }
-  
+
   /**
    * Detemine which versions content with the given library can be upgraded to.
-   * 
+   *
    * @param object $library
    * @param array $versions
    * @return array
@@ -1850,13 +1843,13 @@ class H5PCore {
 
    return $upgrades;
   }
-  
+
   /**
    * Converts all the properties of the given object or array from
    * snake_case to camelCase. Useful after fetching data from the database.
-   * 
+   *
    * Note that some databases does not support camelCase.
-   * 
+   *
    * @param mixed $arr input
    * @param boolean $obj return object
    * @return mixed object or array
@@ -1875,36 +1868,36 @@ class H5PCore {
 
     return $obj ? (object) $newArr : $newArr;
   }
-  
+
   /**
    * Check if currently installed H5P libraries are supported by
    * the current versjon of core. Which versions of which libraries are supported is
    * defined in the library-support.json file.
    *
-   * @param boolean If TRUE, unsupported libraries list are rebuilt. If FALSE, list is 
+   * @param boolean If TRUE, unsupported libraries list are rebuilt. If FALSE, list is
    *                rebuilt only if non-existing
    */
   public function validateLibrarySupport($force = false) {
     if (!($this->h5pF->getUnsupportedLibraries() === NULL || $force)) {
       return;
     }
-    
+
     $minVersions = $this->getMinimumVersionsSupported(realpath(dirname(__FILE__)) . '/library-support.json');
     if ($minVersions === NULL) {
       return;
     }
-    
+
     // Get all libraries installed, check if any of them is not supported:
     $libraries = $this->h5pF->loadLibraries();
     $unsupportedLibraries = array();
-    
+
     // Iterate over all installed libraries
     foreach ($libraries as $library_name => $versions) {
       if (!isset($minVersions[$library_name])) {
         continue;
       }
       $min = $minVersions[$library_name];
-      
+
       // For each version of this library, check if it is supported
       foreach ($versions as $library) {
         if (!$this->isLibraryVersionSupported($library, $min->versions)) {
@@ -1920,23 +1913,23 @@ class H5PCore {
           );
         }
       }
-      
+
       $this->h5pF->setUnsupportedLibraries(empty($unsupportedLibraries) ? NULL : $unsupportedLibraries);
     }
   }
-  
+
   /**
    * Returns a list of the minimum version of libraries that are supported.
    * This is needed because some old libraries are no longer supported by core.
-   * 
+   *
    * TODO: Make it possible for the systems to cache this list between requests.
-   * 
+   *
    * @param string $path to json file
    * @return array indexed using library names
    */
   public function getMinimumVersionsSupported($path) {
     $minSupported = array();
-    
+
     // Get list of minimum version for libraries. Some old libraries are no longer supported.
     $libraries = file_get_contents($path);
     if ($libraries !== FALSE) {
@@ -1950,13 +1943,13 @@ class H5PCore {
         }
       }
     }
-    
+
     return empty($minSupported) ? NULL : $minSupported;
   }
-  
+
   /**
    * Check if a specific version of a library is supported
-   * 
+   *
    * @param object library
    * @param array An array containing versions
    * @return boolean TRUE if supported, otherwise FALSE
@@ -1969,37 +1962,37 @@ class H5PCore {
       // --- minor is higher than any minimumversion for a given major
       // --- major and minor equals and patch is >= supported
       $major_supported |= ($library->major_version > $minimumVersion->major);
-    
+
       if ($library->major_version == $minimumVersion->major) {
         $minor_supported |= ($library->minor_version > $minimumVersion->minor);
       }
-    
+
       if ($library->major_version == $minimumVersion->major &&
           $library->minor_version == $minimumVersion->minor) {
         $patch_supported |= ($library->patch_version >= $minimumVersion->patch);
       }
     }
-    
+
     return ($patch_supported || $minor_supported || $major_supported);
   }
-  
+
   /**
-   * Helper function for creating markup for the unsupported libraries list 
-   * 
+   * Helper function for creating markup for the unsupported libraries list
+   *
    * TODO: Make help text translatable
-   * 
+   *
    * @return string Html
    * */
   public function createMarkupForUnsupportedLibraryList($libraries) {
     $html = '<div><span>The following versions of H5P libraries are not supported anymore:<span><ul>';
-    
+
     foreach ($libraries as $library) {
       $downloadUrl = $library['downloadUrl'];
       $libraryName = $library['name'];
       $currentVersion = $library['currentVersion']['major'] . '.' . $library['currentVersion']['minor'] .'.' . $library['currentVersion']['patch'];
       $html .= "<li><a href=\"$downloadUrl\">$libraryName</a> ($currentVersion)</li>";
     }
-    
+
     $html .= '</ul><span><br>These libraries may cause problems on this site. See <a href="http://h5p.org/releases/h5p-core-1.3">here</a> for more info</div>';
     return $html;
   }
@@ -2038,24 +2031,24 @@ class H5PContentValidator {
       'select' => 'validateSelect',
       'library' => 'validateLibrary',
     );
-    
+
     // Keep track of the libraries we load to avoid loading it multiple times.
     $this->libraries = array();
     // TODO: Should this possible be done in core's loadLibrary? This might be done multiple places.
-    
+
     // Keep track of all dependencies for the given content.
     $this->dependencies = array();
   }
 
   /**
    * Get the flat dependecy tree.
-   * 
+   *
    * @return array
    */
   public function getDependencies() {
     return $this->dependencies;
   }
-  
+
   /**
    * Validate given text value against text semantics.
    */
@@ -2280,19 +2273,19 @@ class H5PContentValidator {
       $validkeys = array_merge($validkeys, $semantics->extraAttributes); // TODO: Validate extraAttributes
     }
     $this->filterParams($file, $validkeys);
-    
+
     if (isset($file->width)) {
       $file->width = intval($file->width);
     }
-    
+
     if (isset($file->height)) {
       $file->height = intval($file->height);
     }
-    
+
     if (isset($file->codecs)) {
       $file->codecs = htmlspecialchars($file->codecs, ENT_QUOTES, 'UTF-8', FALSE);
     }
-    
+
     if (isset($file->quality)) {
       if (!is_object($file->quality) || !isset($file->quality->level) || !isset($file->quality->label)) {
         unset($file->quality);
@@ -2303,7 +2296,7 @@ class H5PContentValidator {
         $file->quality->label = htmlspecialchars($file->quality->label, ENT_QUOTES, 'UTF-8', FALSE);
       }
     }
-    
+
     if (isset($file->copyright)) {
       $this->validateGroup($file->copyright, H5PContentValidator::getCopyrightSemantics());
     }
@@ -2406,11 +2399,11 @@ class H5PContentValidator {
       $value = new stdClass();
       return;
     }
-    
+
     if (!isset($this->libraries[$value->library])) {
       $libspec = H5PCore::libraryFromString($value->library);
       $library = $this->h5pC->loadLibrary($libspec['machineName'], $libspec['majorVersion'], $libspec['minorVersion']);
-      $library['semantics'] = json_decode($library['semantics']);
+      $library['semantics'] = $this->h5pC->loadLibrarySemantics($libspec['machineName'], $libspec['majorVersion'], $libspec['minorVersion']);
       $this->libraries[$value->library] = $library;
 
       // Find all dependencies for this library
@@ -2700,7 +2693,7 @@ class H5PContentValidator {
 
   /**
    * Processes an HTML attribute value and strips dangerous protocols from URLs.
-   *   
+   *
    * @param $string
    *   The string with the attribute value.
    * @param $decode
@@ -2773,10 +2766,10 @@ class H5PContentValidator {
 
     return $uri;
   }
-  
+
   public static function getCopyrightSemantics() {
     static $semantics;
-    
+
     if ($semantics === NULL) {
       $semantics = (object) array(
         'name' => 'copyright',
@@ -2874,7 +2867,7 @@ class H5PContentValidator {
         )
       );
     }
-    
+
     return $semantics;
   }
 }
diff --git a/js/h5p-content-upgrade.js b/js/h5p-content-upgrade.js
index c5cd02a..ff3756f 100644
--- a/js/h5p-content-upgrade.js
+++ b/js/h5p-content-upgrade.js
@@ -213,18 +213,28 @@ var H5PUpgrades = H5PUpgrades || {};
     var current = 0; // Track progress
     asyncSerial(parameters, function (id, params, next) {
 
-      // Make params possible to work with
-      params = JSON.parse(params);
+      try {
+        // Make params possible to work with
+        params = JSON.parse(params);
+        if (!(params instanceof Object)) {
+          throw true;
+        }
+      }
+      catch (event) {
+        return next(info.errorContent.replace('%id', id) + ' ' + info.errorParamsBroken);
+      }
 
       // Upgrade this content.
       self.upgrade(info.library.name, new Version(info.library.version), self.version, params, function (err, params) {
-        if (!err) {
-          upgraded[id] = JSON.stringify(params);
-
-          current++;
-          self.throbber.setProgress(Math.round((info.total - self.left + current) / (info.total / 100)) + ' %');
+        if (err) {
+          return next(info.errorContent.replace('%id', id) + ' ' + err);
         }
-        next(err);
+
+        upgraded[id] = JSON.stringify(params);
+
+        current++;
+        self.throbber.setProgress(Math.round((info.total - self.left + current) / (info.total / 100)) + ' %');
+        next();
       });
 
     }, function (err) {
@@ -375,14 +385,16 @@ var H5PUpgrades = H5PUpgrades || {};
           }
           else {
             // We found an upgrade hook, run it
-            if (upgrade.contentUpgrade !== undefined && typeof upgrade.contentUpgrade === 'function') {
-              upgrade.contentUpgrade(params, function (err, upgradedParams) {
+            var unnecessaryWrapper = (upgrade.contentUpgrade !== undefined ? upgrade.contentUpgrade : upgrade);
+
+            try {
+              unnecessaryWrapper(params, function (err, upgradedParams) {
                 params = upgradedParams;
                 nextMinor(err);
               });
             }
-            else {
-              nextMinor(info.errorScript.replace('%lib', library.name + ' ' + newVersion));
+            catch (err) {
+              next(err);
             }
           }
         }, nextMajor);
diff --git a/styles/h5p-admin.css b/styles/h5p-admin.css
index 44310b0..219309a 100644
--- a/styles/h5p-admin.css
+++ b/styles/h5p-admin.css
@@ -244,4 +244,7 @@ button.h5p-admin.disabled:hover {
   padding: 0 0.5em;
   font-size: 1.5em;
   font-weight: bold;
-}
\ No newline at end of file
+}
+#h5p-admin-container .h5p-admin-center {
+  text-align: center;
+}