diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index fbf7b9d..8e2a866 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,6 +1,10 @@
 Changelog
 ========
 
+* 0.5.7 (January 23rd, 2017)
+    * Fixed additional issues downloading PDFs in Python 3
+    * Fixed issues caused by hard coded content-type for attachables.
+
 * 0.5.6 (January 18th, 2017)
     * Fixed issue downloading PDFs in Python 3
 
diff --git a/quickbooks/client.py b/quickbooks/client.py
index ce994ed..8569dc0 100644
--- a/quickbooks/client.py
+++ b/quickbooks/client.py
@@ -255,7 +255,7 @@ def make_request(self, request_type, url, request_body=None, content_type='appli
                 'Connection': 'close'
             })
 
-            binary_data = str(base64.b64encode(attachment.read()), 'utf-8')
+            binary_data = str(base64.b64encode(attachment.read()))
 
             content_type = json.loads(request_body)['ContentType']
 
diff --git a/setup.py b/setup.py
index 02b87e3..3661eb1 100644
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@ def read(*parts):
         return fp.read()
 
 
-VERSION = (0, 5, 6)
+VERSION = (0, 5, 7)
 version = '.'.join(map(str, VERSION))
 
 setup(