diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 99e2b8139f4..282ba44572f 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -2674,5 +2674,20 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2013100900.00);
     }
 
+    if ($oldversion < 2013100901.00) {
+        // Fixing possible wrong MIME type for Java Network Launch Protocol (JNLP) files.
+        $select = $DB->sql_like('filename', '?', false);
+        $DB->set_field_select(
+            'files',
+            'mimetype',
+            'application/x-java-jnlp-file',
+            $select,
+            array('%.jnlp')
+        );
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2013100901.00);
+    }
+
     return true;
 }
diff --git a/lib/filelib.php b/lib/filelib.php
index 3674d5c3d51..364e43f0289 100644
--- a/lib/filelib.php
+++ b/lib/filelib.php
@@ -1451,6 +1451,7 @@ function &get_mimetypes_array() {
         'jcw'  => array ('type'=>'text/xml', 'icon'=>'markup'),
         'jmt'  => array ('type'=>'text/xml', 'icon'=>'markup'),
         'jmx'  => array ('type'=>'text/xml', 'icon'=>'markup'),
+        'jnlp' => array ('type'=>'application/x-java-jnlp-file', 'icon'=>'markup'),
         'jpe'  => array ('type'=>'image/jpeg', 'icon'=>'jpeg', 'groups'=>array('image', 'web_image'), 'string'=>'image'),
         'jpeg' => array ('type'=>'image/jpeg', 'icon'=>'jpeg', 'groups'=>array('image', 'web_image'), 'string'=>'image'),
         'jpg'  => array ('type'=>'image/jpeg', 'icon'=>'jpeg', 'groups'=>array('image', 'web_image'), 'string'=>'image'),
diff --git a/version.php b/version.php
index c5bcfafcc2a..2b875e96e6e 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2013100900.00;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2013100901.00;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.