fixed doc (closes #744)

diff --git a/doc/filters/convert_encoding.rst b/doc/filters/convert_encoding.rst
index be40b0d..2febab2 100644 (file)
--- a/doc/filters/convert_encoding.rst
+++ b/doc/filters/convert_encoding.rst
@@ -15,8 +15,8 @@ is the input charset:
 .. note::
 
     This filter relies on the `iconv`_ or `mbstring`_ extension, so one of
-    them must be installed. In case both are installed, `iconv`_ is used
-    by default.
+    them must be installed. In case both are installed, `mbstring`_ is used by
+    default (Twig before 1.8.1 uses `iconv`_ by default).
 
 .. _`iconv`:    http://php.net/iconv
 .. _`mbstring`: http://php.net/mbstring