diff --git a/.travis.yml b/.travis.yml
index 2790134e..9c49978d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,4 +2,5 @@ language: php
 php:
   - 5.3
   - 5.4
+  - 5.5
 script: phpunit --stderr --bootstrap tests/bootstrap.php tests/tests.php
diff --git a/src/base_facebook.php b/src/base_facebook.php
index 2d1d45c5..f6ed47a4 100644
--- a/src/base_facebook.php
+++ b/src/base_facebook.php
@@ -901,7 +901,7 @@ protected function _oauthRequest($url, $params) {
 
     // json_encode all params values that are not strings
     foreach ($params as $key => $value) {
-      if (!is_string($value)) {
+      if (!is_string($value) && !($value instanceof CURLFile)) {
         $params[$key] = json_encode($value);
       }
     }