diff --git a/reference/constraints/File.rst b/reference/constraints/File.rst
index c06a20fd71b..1759cf374cd 100644
--- a/reference/constraints/File.rst
+++ b/reference/constraints/File.rst
@@ -20,6 +20,7 @@ form type.
 | Applies to     | :ref:`property or method <validation-property-target>`              |
 +----------------+---------------------------------------------------------------------+
 | Options        | - `maxSize`_                                                        |
+|                | - `binaryFormat`_                                                   |
 |                | - `mimeTypes`_                                                      |
 |                | - `maxSizeMessage`_                                                 |
 |                | - `mimeTypesMessage`_                                               |
@@ -79,7 +80,6 @@ below a certain file size and a valid PDF, add the following:
                         maxSize: 1024k
                         mimeTypes: [application/pdf, application/x-pdf]
                         mimeTypesMessage: Please upload a valid PDF
-                        
 
     .. code-block:: php-annotations
 
@@ -155,19 +155,46 @@ Options
 maxSize
 ~~~~~~~
 
+.. versionadded:: 2.6
+    The suffixes ``Ki`` and ``Mi`` were introduced in Symfony 2.6.
+
 **type**: ``mixed``
 
 If set, the size of the underlying file must be below this file size in order
 to be valid. The size of the file can be given in one of the following formats:
 
-* **bytes**: To specify the ``maxSize`` in bytes, pass a value that is entirely
-  numeric (e.g. ``4096``);
++--------+-----------+-----------------+------+
+| Suffix | Unit Name |      value      | e.g. |
++========+===========+=================+======+
+|        | byte      |          1 byte | 4096 |
++--------+-----------+-----------------+------+
+| k      | kilobyte  |     1,000 bytes | 200k |
++--------+-----------+-----------------+------+
+| M      | megabyte  | 1,000,000 bytes |   2M |
++--------+-----------+-----------------+------+
+| Ki     | kibibyte  |     1,024 bytes | 32Ki |
++--------+-----------+-----------------+------+
+| Mi     | mebibyte  | 1,048,576 bytes |  8Mi |
++--------+-----------+-----------------+------+
+
+For more information about the difference between binary and SI suffixes,
+see `Wikipedia: Binary prefix`_.
+
+binaryFormat
+~~~~~~~~~~~~
+
+.. versionadded:: 2.6
+    The ``binaryFormat`` option was introduced in Symfony 2.6.
+
+**type**: ``boolean`` **default**: ``null``
 
-* **kilobytes**: To specify the ``maxSize`` in kilobytes, pass a number and
-  suffix it with a lowercase "k" (e.g. ``200k``);
+When ``true``, the sizes will be displayed in messages with binary suffixes
+(KiB, MiB). When ``false``, the sizes will be displayed with SI suffixes (kB,
+MB). When ``null``, then the binaryFormat will be guessed from the suffix
+defined in the ``maxSize`` option.
 
-* **megabytes**: To specify the ``maxSize`` in megabytes, pass a number and
-  suffix it with a capital "M" (e.g. ``4M``).
+For more information about the difference between binary and SI suffixes,
+see `Wikipedia: Binary prefix`_.
 
 mimeTypes
 ~~~~~~~~~
@@ -251,3 +278,4 @@ to disk.
 
 
 .. _`IANA website`: http://www.iana.org/assignments/media-types/index.html
+.. _`Wikipedia: Binary prefix`: http://en.wikipedia.org/wiki/Binary_prefix