diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 520efb0..2750cc5 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -29,15 +29,12 @@ Make sure to run tests/run.sh before each PR.
 
 ## How to release
 
-- Make sure you have update osc_api submodule by running `make osc-api-update`
-- Have `OSC_ACCESS_KEY` and `OSC_SECRET_KEY` environment variables set for `eu-west-2` region
-- Run all tests with `make test`
 - Update version in:
   - [osc_sdk_python/VERSION](osc_sdk_python/VERSION)
   - [README.md](README.md)
-- Push PR, validate changes and merge into `master` branch
-- Push corresponding tag
-- Tag and push branch
-- Create release
-- Add `dist/osc_sdk_python-x.x.x-py3-none-any.whl` and `osc_sdk_python-x.x.x.tar.gz` files to release.
-- Github action should have pushed packages on pip. If not: setup PIP_TOKEN and run `make upload-package`
+- Commit, PR, merge
+- Create release in Github
+- Github action should have generated artifacts. If not:
+  - `make package`
+  - Add `dist/osc_sdk_python-x.x.x-py3-none-any.whl` and `osc_sdk_python-x.x.x.tar.gz` files to release.
+  - Setup PIP_TOKEN and run `make upload-package`
diff --git a/README.md b/README.md
index ba56f35..8d6fdc7 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ $ make package
 
 You can then install it with:
 ```bash
-$ pip install dist/osc_sdk_python-0.21.0-py3-none-any.whl
+$ pip install dist/osc_sdk_python-0.21.1-py3-none-any.whl
 ```
 
 # Configuration & Credentials
diff --git a/osc_sdk_python/VERSION b/osc_sdk_python/VERSION
index 8854156..a67ceba 100644
--- a/osc_sdk_python/VERSION
+++ b/osc_sdk_python/VERSION
@@ -1 +1 @@
-0.21.0
+0.21.1
diff --git a/osc_sdk_python/credentials.py b/osc_sdk_python/credentials.py
index 7c23500..5e996ed 100644
--- a/osc_sdk_python/credentials.py
+++ b/osc_sdk_python/credentials.py
@@ -9,10 +9,14 @@
 class Credentials:
     def __init__(self, region, profile, access_key, secret_key, email, password):
         self.region = None
+        self.access_key = access_key
+        self.secret_key = secret_key
+        self.email = email
+        self.password = password
 
         if profile is None:
             profile = os.environ.get('OSC_PROFILE')
-        if profile != None:
+        else:
             # Overide with environmental configuration if available
             self.load_credentials_from_env()
         # Overide with old configuration if available
@@ -25,7 +29,7 @@ def __init__(self, region, profile, access_key, secret_key, email, password):
             self.load_credentials_from_env()
 
         # Set defaults
-        if region != None:
+        if region is not None:
             self.region = region
 
         if self.region is None:
@@ -33,12 +37,10 @@ def __init__(self, region, profile, access_key, secret_key, email, password):
 
         self.profile = profile
         # Overide with app parameters if provided
-        if access_key != None:
+        if access_key is not None:
             self.access_key = access_key
-        if secret_key != None:
+        if secret_key is not None:
             self.secret_key = secret_key
-        self.email = email
-        self.password = password
 
         self.check_options()
 
@@ -47,42 +49,44 @@ def load_credentials_from_file(self, profile, file_path):
             with open(file_path) as f:
                 config = json.load(f)
                 profile = config.get(profile)
-                if profile == None:
+                if profile is None:
                     return
                 ak = profile.get("access_key")
-                if ak != None:
+                if ak is not None:
                     self.access_key = ak
                 sk = profile.get("secret_key")
-                if sk != None:
+                if sk is not None:
                     self.secret_key = sk
                 region = profile.get("region")
-                if region != None:
+                if region is not None:
                     self.region = region
         except IOError:
             pass
 
     def load_credentials_from_env(self):
         ak = os.environ.get('OSC_ACCESS_KEY')
-        if ak != None:
+        if ak is not None:
             self.access_key = ak
         sk = os.environ.get('OSC_SECRET_KEY')
-        if sk != None:
+        if sk is not None:
             self.secret_key = sk
         region = os.environ.get('OSC_REGION')
-        if region != None:
+        if region is not None:
             self.region = region
 
     def check_options(self):
-        if self.access_key == None or len(self.access_key) == 0:
-            raise Exception("Invalid Outscale access key")
-        if self.secret_key == None or len(self.secret_key) == 0:
-            raise Exception("Invalid Outscale secret key")
-        if self.region == None or len(self.region) == 0:
+        if self.access_key is not None or self.secret_key is not None:
+            if self.access_key is None or len(self.access_key) == 0:
+                raise Exception("Invalid Outscale access key")
+            if self.secret_key is None or len(self.secret_key) == 0:
+                raise Exception("Invalid Outscale secret key")
+        elif self.email is not None or self.password is not None:
+            if self.email is None or len(self.email) == 0:
+                raise Exception("Invalid email option")
+            if self.password is None and self.password == 0:
+                raise Exception("Invalid password option")
+        if self.region is None or len(self.region) == 0:
             raise Exception("Invalid Outscale region")
-        if self.email is None and self.password is not None:
-            raise Exception("Missing email option with password option")
-        if self.email is not None and self.password is None:
-            raise Exception("Missing password option with email option")
 
     def get_url_extension(self):
         return 'hk' if 'cn' in self.region else 'com'
diff --git a/osc_sdk_python/osc-api b/osc_sdk_python/osc-api
index 8d8ed08..49cd2da 160000
--- a/osc_sdk_python/osc-api
+++ b/osc_sdk_python/osc-api
@@ -1 +1 @@
-Subproject commit 8d8ed08551bf8474c41480c499d1136d3aef3083
+Subproject commit 49cd2da047e0d02c04e3d954f889c46cde1122e8
diff --git a/tests/test_manual_aksk.py b/tests/test_manual_aksk.py
new file mode 100644
index 0000000..428e887
--- /dev/null
+++ b/tests/test_manual_aksk.py
@@ -0,0 +1,20 @@
+import unittest
+import sys
+import os
+sys.path.append("..")
+from osc_sdk_python import Gateway
+
+class TestLoginManualAkSk(unittest.TestCase):
+
+    def test_manual_ak_sk(self):
+        ak = os.environ.pop("OSC_ACCESS_KEY", None)
+        sk = os.environ.pop("OSC_SECRET_KEY", None)
+        self.assertNotEqual(ak, None)
+        self.assertNotEqual(sk, None)
+        gw = Gateway(access_key=ak, secret_key=sk)
+        volumes = gw.ReadVolumes()
+        self.assertEqual(type(volumes), dict)
+        self.assertEqual(type(volumes.get("Volumes")), list)
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/tests/test_password.py b/tests/test_password.py
index e262061..00a5ae9 100644
--- a/tests/test_password.py
+++ b/tests/test_password.py
@@ -7,6 +7,8 @@
 class TestLoginPassword(unittest.TestCase):
 
     def test_login(self):
+        os.environ.pop("OSC_ACCESS_KEY", None)
+        os.environ.pop("OSC_SECRET_KEY", None)
         email = os.getenv('OSC_TEST_LOGIN')
         password = os.getenv('OSC_TEST_PASSWORD')
         self.assertNotEqual(email, None)