diff --git a/CHANGES.md b/CHANGES.md
index 4e4ace5..ab8e32b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,12 @@
 # SQLAlchemy-JSONAPI Changelog
 
+## 4.0.1 - 4.0.3
+
+*2016-01-21*
+
+* Fixed bug where the wrong map was being checked when creating new resource
+* Fixed content-length bug when DELETE is provided for resources
+
 ## 4.0.0
 
 *2016-01-20*
diff --git a/setup.py b/setup.py
index 6c99dfc..5c6bd66 100644
--- a/setup.py
+++ b/setup.py
@@ -21,7 +21,7 @@
       requirements.append('enum34')
 
 setup(name='SQLAlchemy-JSONAPI',
-      version='4.0.0',
+      version='4.0.3',
       url='http://github.com/coltonprovias/sqlalchemy-jsonapi',
       license='MIT',
       author='Colton J. Provias',
diff --git a/sqlalchemy_jsonapi/flaskext.py b/sqlalchemy_jsonapi/flaskext.py
index 94a8a9b..2548d32 100644
--- a/sqlalchemy_jsonapi/flaskext.py
+++ b/sqlalchemy_jsonapi/flaskext.py
@@ -188,7 +188,8 @@ def new_view(**kwargs):
             if method == Method.GET:
                 data = request.args
             else:
-                if int(request.headers.get('content-length', 0)) > 0:
+                content_length = request.headers.get('content-length', 0)
+                if content_length and int(content_length) > 0:
                     content_type = request.headers.get('content-type', None)
                     if content_type != 'application/vnd.api+json':
                         data = MissingContentTypeError().data
diff --git a/sqlalchemy_jsonapi/serializer.py b/sqlalchemy_jsonapi/serializer.py
index 48463d2..5e24c11 100644
--- a/sqlalchemy_jsonapi/serializer.py
+++ b/sqlalchemy_jsonapi/serializer.py
@@ -140,7 +140,7 @@ def __init__(self):
         self.status_code = 200
         self.data = {
             'jsonapi': {'version': '1.0'},
-            'meta': {'sqlalchemy_jsonapi_version': '4.0.1'}
+            'meta': {'sqlalchemy_jsonapi_version': '4.0.3'}
         }
 
 
@@ -974,13 +974,13 @@ def post_collection(self, session, data, api_type):
 
             for key, relationship in resource.__mapper__.relationships.items():
                 attrs_to_ignore |= set(relationship.local_columns) | {key}
-                py_key = resource.__jsonapi_map_to_py__[key]
+                api_key = resource.__jsonapi_map_to_api__[key]
 
                 if 'relationships' not in data['data'].keys()\
-                        or py_key not in data['data']['relationships'].keys():
+                        or api_key not in data['data']['relationships'].keys():
                     continue
 
-                data_rel = data['data']['relationships'][key]
+                data_rel = data['data']['relationships'][api_key]
                 if 'data' not in data_rel.keys():
                     raise BadRequestError(
                         'Missing data key in relationship {}'.format(key))
@@ -988,7 +988,7 @@ def post_collection(self, session, data, api_type):
 
                 remote_side = relationship.back_populates
                 if relationship.direction == MANYTOONE:
-                    setter = get_rel_desc(resource, py_key,
+                    setter = get_rel_desc(resource, key,
                                           RelationshipActions.SET)
                     if data_rel is None:
                         setters.append([setter, None])
@@ -1011,7 +1011,7 @@ def post_collection(self, session, data, api_type):
                                              Permissions.CREATE)
                         setters.append([setter, to_relate])
                 else:
-                    setter = get_rel_desc(resource, py_key,
+                    setter = get_rel_desc(resource, key,
                                           RelationshipActions.APPEND)
                     if not isinstance(data_rel, list):
                         raise BadRequestError(