In php file: /lib/filelib.php function send_stored_file Around lines: 2353 Description: I solved the problem changing the mimetype for android web browser. It's a bug of android web browser but with this patch we can fix it. I force all resource on android to download and there get the correct app. Original Code : // Use given MIME type if specified, otherwise guess it using mimeinfo. // IE, Konqueror and Opera open html file directly in browser from web even when directed to save it to disk :-O // only Firefox saves all files locally before opening when content-disposition: attachment stated $filename = is_null($filename) ? $stored_file->get_filename() : $filename; $isFF = check_browser_version('Firefox', '1.5'); // only FF > 1.5 properly tested $mimetype = ($forcedownload and !$isFF) ? 'application/x-forcedownload' : ($stored_file->get_mimetype() ? $stored_file->get_mimetype() : mimeinfo('type', $filename));   // if user is using IE, urlencode the filename so that multibyte file name will show up correctly on popup Modified Code: // Use given MIME type if specified, otherwise guess it using mimeinfo. // IE, Konqueror and Opera open html file directly in browser from web even when directed to save it to disk :-O // only Firefox saves all files locally before opening when content-disposition: attachment stated $filename = is_null($filename) ? $stored_file->get_filename() : $filename; $isFF = check_browser_version('Firefox', '1.5'); // only FF > 1.5 properly tested $mimetype = ($forcedownload and !$isFF) ? 'application/x-forcedownload' : ($stored_file->get_mimetype() ? $stored_file->get_mimetype() : mimeinfo('type', $filename)); $isANDROID = check_browser_version('WebKit Android'); //Android web browser if($isANDROID) $mimetype = ($stored_file->get_mimetype() ? $stored_file->get_mimetype() : mimeinfo('type', $filename)); if($isANDROID) $forcedownload = true; // Force download to any type of resource configuration. // if user is using IE, urlencode the filename so that multibyte file name will show up correctly on popup ...

In any resource configuration (Force Download, embed, in pop-up, ...) Use a Android web browser to enter into a course and try to download any type of resource PDF. After try to download the result is a corrupt PDF. And its the same in Android web browser 4.0