From eb1b6e34c71abe45d96cbf356f1253a3ca5c51a6 Mon Sep 17 00:00:00 2001
From: Ross Lawley <ross.lawley@gmail.com>
Date: Fri, 25 Jan 2013 11:51:58 +0000
Subject: [PATCH] Updated upgrade docs (#49)

---
 docs/upgrade.rst | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/docs/upgrade.rst b/docs/upgrade.rst
index 9c6c9a9d..d3282487 100644
--- a/docs/upgrade.rst
+++ b/docs/upgrade.rst
@@ -56,6 +56,26 @@ you will need to declare :attr:`allow_inheritance` in the meta data like so: ::
 
         meta = {'allow_inheritance': True}
 
+Previously, if you had data the database that wasn't defined in the Document
+definition, it would set it as an attribute on the document.  This is no longer
+the case and the data is set only in the ``document._data`` dictionary: ::
+
+    >>> from mongoengine import *
+    >>> class Animal(Document):
+    ...    name = StringField()
+    ...
+    >>> cat = Animal(name="kit", size="small")
+
+    # 0.7
+    >>> cat.size
+    u'small'
+
+    # 0.8
+    >>> cat.size
+    Traceback (most recent call last):
+      File "<stdin>", line 1, in <module>
+    AttributeError: 'Animal' object has no attribute 'size'
+
 Querysets
 ~~~~~~~~~