diff --git a/mayan/apps/common/tests/test_compressed_files.py b/mayan/apps/common/tests/test_compressed_files.py
index 597bd06c42..a89d0d3f61 100644
--- a/mayan/apps/common/tests/test_compressed_files.py
+++ b/mayan/apps/common/tests/test_compressed_files.py
@@ -23,22 +23,22 @@ class TarArchiveClassTestCase(BaseTestCase):
     def test_add_file(self):
         archive = self.cls()
         archive.create()
-        with open(self.file_path, 'rb') as file_object:
+        with open(self.file_path, mode='rb') as file_object:
             archive.add_file(file_object=file_object, filename=self.filename)
             self.assertTrue(archive.members(), [self.filename])
 
     def test_open(self):
-        with open(self.archive_path, 'rb') as file_object:
+        with open(self.archive_path, mode='rb') as file_object:
             archive = Archive.open(file_object=file_object)
             self.assertTrue(isinstance(archive, self.cls))
 
     def test_members(self):
-        with open(self.archive_path, 'rb') as file_object:
+        with open(self.archive_path, mode='rb') as file_object:
             archive = Archive.open(file_object=file_object)
             self.assertEqual(archive.members(), self.members_list)
 
     def test_member_contents(self):
-        with open(self.archive_path, 'rb') as file_object:
+        with open(self.archive_path, mode='rb') as file_object:
             archive = Archive.open(file_object=file_object)
             self.assertEqual(
                 archive.member_contents(filename=self.member_name),
@@ -46,7 +46,7 @@ class TarArchiveClassTestCase(BaseTestCase):
             )
 
     def test_open_member(self):
-        with open(self.archive_path, 'rb') as file_object:
+        with open(self.archive_path, mode='rb') as file_object:
             archive = Archive.open(file_object=file_object)
             file_object = archive.open_member(filename=self.member_name)
             self.assertEqual(
diff --git a/mayan/apps/common/utils.py b/mayan/apps/common/utils.py
index bbe8b90e99..48b509f2b6 100644
--- a/mayan/apps/common/utils.py
+++ b/mayan/apps/common/utils.py
@@ -102,9 +102,9 @@ def get_descriptor(file_input, read=True):
     except AttributeError:
         # If not, try open it.
         if read:
-            return open(file_input, 'rb')
+            return open(file_input, mode='rb')
         else:
-            return open(file_input, 'wb')
+            return open(file_input, mode='wb')
     else:
         return file_input
 
diff --git a/mayan/apps/django_gpg/tests/test_models.py b/mayan/apps/django_gpg/tests/test_models.py
index 80718550df..99261d9a5f 100644
--- a/mayan/apps/django_gpg/tests/test_models.py
+++ b/mayan/apps/django_gpg/tests/test_models.py
@@ -86,7 +86,7 @@ class KeyTestCase(BaseTestCase):
         cleartext_file.close()
 
     def test_embedded_verification_no_key(self):
-        with open(TEST_SIGNED_FILE, 'rb') as signed_file:
+        with open(TEST_SIGNED_FILE, mode='rb') as signed_file:
             result = Key.objects.verify_file(signed_file)
 
         self.assertTrue(result.key_id in TEST_KEY_FINGERPRINT)
@@ -94,7 +94,7 @@ class KeyTestCase(BaseTestCase):
     def test_embedded_verification_with_key(self):
         Key.objects.create(key_data=TEST_KEY_DATA)
 
-        with open(TEST_SIGNED_FILE, 'rb') as signed_file:
+        with open(TEST_SIGNED_FILE, mode='rb') as signed_file:
             result = Key.objects.verify_file(signed_file)
 
         self.assertEqual(result.fingerprint, TEST_KEY_FINGERPRINT)
@@ -102,7 +102,7 @@ class KeyTestCase(BaseTestCase):
     def test_embedded_verification_with_correct_fingerprint(self):
         Key.objects.create(key_data=TEST_KEY_DATA)
 
-        with open(TEST_SIGNED_FILE, 'rb') as signed_file:
+        with open(TEST_SIGNED_FILE, mode='rb') as signed_file:
             result = Key.objects.verify_file(
                 signed_file, key_fingerprint=TEST_KEY_FINGERPRINT
             )
@@ -113,14 +113,14 @@ class KeyTestCase(BaseTestCase):
     def test_embedded_verification_with_incorrect_fingerprint(self):
         Key.objects.create(key_data=TEST_KEY_DATA)
 
-        with open(TEST_SIGNED_FILE, 'rb') as signed_file:
+        with open(TEST_SIGNED_FILE, mode='rb') as signed_file:
             with self.assertRaises(KeyDoesNotExist):
                 Key.objects.verify_file(signed_file, key_fingerprint='999')
 
     def test_signed_file_decryption(self):
         Key.objects.create(key_data=TEST_KEY_DATA)
 
-        with open(TEST_SIGNED_FILE, 'rb') as signed_file:
+        with open(TEST_SIGNED_FILE, mode='rb') as signed_file:
             result = Key.objects.decrypt_file(file_object=signed_file)
 
         self.assertEqual(result.read(), TEST_SIGNED_FILE_CONTENT)
@@ -136,8 +136,8 @@ class KeyTestCase(BaseTestCase):
         cleartext_file.close()
 
     def test_detached_verification_no_key(self):
-        with open(TEST_DETACHED_SIGNATURE, 'rb') as signature_file:
-            with open(TEST_FILE, 'rb') as test_file:
+        with open(TEST_DETACHED_SIGNATURE, mode='rb') as signature_file:
+            with open(TEST_FILE, mode='rb') as test_file:
                 result = Key.objects.verify_file(
                     file_object=test_file, signature_file=signature_file
                 )
@@ -147,8 +147,8 @@ class KeyTestCase(BaseTestCase):
     def test_detached_verification_with_key(self):
         Key.objects.create(key_data=TEST_KEY_DATA)
 
-        with open(TEST_DETACHED_SIGNATURE, 'rb') as signature_file:
-            with open(TEST_FILE, 'rb') as test_file:
+        with open(TEST_DETACHED_SIGNATURE, mode='rb') as signature_file:
+            with open(TEST_FILE, mode='rb') as test_file:
                 result = Key.objects.verify_file(
                     file_object=test_file, signature_file=signature_file
                 )
@@ -160,7 +160,7 @@ class KeyTestCase(BaseTestCase):
         key = Key.objects.create(key_data=TEST_KEY_DATA)
 
         with self.assertRaises(NeedPassphrase):
-            with open(TEST_FILE, 'rb') as test_file:
+            with open(TEST_FILE, mode='rb') as test_file:
                 key.sign_file(
                     file_object=test_file, detached=True,
                 )
@@ -169,7 +169,7 @@ class KeyTestCase(BaseTestCase):
         key = Key.objects.create(key_data=TEST_KEY_DATA)
 
         with self.assertRaises(PassphraseError):
-            with open(TEST_FILE, 'rb') as test_file:
+            with open(TEST_FILE, mode='rb') as test_file:
                 key.sign_file(
                     file_object=test_file, detached=True,
                     passphrase='bad passphrase'
@@ -178,7 +178,7 @@ class KeyTestCase(BaseTestCase):
     def test_detached_signing_with_passphrase(self):
         key = Key.objects.create(key_data=TEST_KEY_DATA)
 
-        with open(TEST_FILE, 'rb') as test_file:
+        with open(TEST_FILE, mode='rb') as test_file:
             detached_signature = key.sign_file(
                 file_object=test_file, detached=True,
                 passphrase=TEST_KEY_PASSPHRASE
@@ -188,7 +188,7 @@ class KeyTestCase(BaseTestCase):
         signature_file.write(force_bytes(detached_signature))
         signature_file.seek(0)
 
-        with open(TEST_FILE, 'rb') as test_file:
+        with open(TEST_FILE, mode='rb') as test_file:
             result = Key.objects.verify_file(
                 file_object=test_file, signature_file=signature_file
             )
diff --git a/mayan/apps/document_signatures/managers.py b/mayan/apps/document_signatures/managers.py
index 050eaf8f20..edebf7c763 100644
--- a/mayan/apps/document_signatures/managers.py
+++ b/mayan/apps/document_signatures/managers.py
@@ -40,7 +40,7 @@ class EmbeddedSignatureManager(models.Manager):
         except Exception:
             raise
         else:
-            with open(temporary_filename, 'rb') as file_object:
+            with open(temporary_filename, mode='rb') as file_object:
                 new_version = document_version.document.new_version(
                     file_object=file_object, _user=user
                 )
diff --git a/mayan/apps/document_states/tests/test_api.py b/mayan/apps/document_states/tests/test_api.py
index 1720ce5c21..97f6340679 100644
--- a/mayan/apps/document_states/tests/test_api.py
+++ b/mayan/apps/document_states/tests/test_api.py
@@ -38,7 +38,7 @@ class WorkflowAPITestCase(BaseAPITestCase):
             label=TEST_DOCUMENT_TYPE_LABEL
         )
 
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             self.document = self.document_type.new_document(
                 file_object=file_object
             )
@@ -372,7 +372,7 @@ class WorkflowStatesAPITestCase(BaseAPITestCase):
             label=TEST_DOCUMENT_TYPE_LABEL
         )
 
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             self.document = self.document_type.new_document(
                 file_object=file_object
             )
@@ -548,7 +548,7 @@ class WorkflowTransitionsAPITestCase(BaseAPITestCase):
             label=TEST_DOCUMENT_TYPE_LABEL
         )
 
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             self.document = self.document_type.new_document(
                 file_object=file_object
             )
@@ -790,7 +790,7 @@ class DocumentWorkflowsAPITestCase(BaseAPITestCase):
         super(DocumentWorkflowsAPITestCase, self).tearDown()
 
     def _create_document(self):
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             self.document = self.document_type.new_document(
                 file_object=file_object
             )
diff --git a/mayan/apps/document_states/tests/test_models.py b/mayan/apps/document_states/tests/test_models.py
index 21c0a97fb0..91fc868896 100644
--- a/mayan/apps/document_states/tests/test_models.py
+++ b/mayan/apps/document_states/tests/test_models.py
@@ -30,7 +30,7 @@ class DocumentStateIndexingTestCase(BaseTestCase):
         )
 
     def _create_document(self):
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             self.document = self.document_type.new_document(
                 file_object=file_object
             )
diff --git a/mayan/apps/documents/models.py b/mayan/apps/documents/models.py
index 3db0fe854d..f5b973e01d 100644
--- a/mayan/apps/documents/models.py
+++ b/mayan/apps/documents/models.py
@@ -529,7 +529,7 @@ class DocumentVersion(models.Model):
                 converter = converter_class(file_object=self.open())
                 pdf_file_object = converter.to_pdf()
 
-                with storage_documentimagecache.open(cache_filename, 'wb+') as file_object:
+                with storage_documentimagecache.open(cache_filename, mode='wb+') as file_object:
                     for chunk in pdf_file_object:
                         file_object.write(chunk)
 
diff --git a/mayan/apps/linking/tests/test_api.py b/mayan/apps/linking/tests/test_api.py
index 2efdac2aa7..90fb862bc2 100644
--- a/mayan/apps/linking/tests/test_api.py
+++ b/mayan/apps/linking/tests/test_api.py
@@ -207,7 +207,7 @@ class SmartLinkConditionAPITestCase(BaseAPITestCase):
         )
 
     def _create_document(self):
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             self.document = self.document_type.new_document(
                 file_object=file_object
             )
diff --git a/mayan/apps/metadata/tests/test_api.py b/mayan/apps/metadata/tests/test_api.py
index fc7d45a6a9..1bca004022 100644
--- a/mayan/apps/metadata/tests/test_api.py
+++ b/mayan/apps/metadata/tests/test_api.py
@@ -354,7 +354,7 @@ class DocumentMetadataAPITestCase(BaseAPITestCase):
             metadata_type=self.metadata_type, required=False
         )
 
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             self.document = self.document_type.new_document(
                 file_object=file_object,
             )
diff --git a/mayan/apps/metadata/tests/test_views.py b/mayan/apps/metadata/tests/test_views.py
index c0c2d5a787..edff891e06 100644
--- a/mayan/apps/metadata/tests/test_views.py
+++ b/mayan/apps/metadata/tests/test_views.py
@@ -201,7 +201,7 @@ class DocumentMetadataTestCase(GenericDocumentViewTestCase):
         self.grant_permission(permission=permission_metadata_document_add)
         self.grant_permission(permission=permission_metadata_document_edit)
 
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             document_2 = self.document_type.new_document(
                 file_object=File(file_object)
             )
@@ -247,7 +247,7 @@ class DocumentMetadataTestCase(GenericDocumentViewTestCase):
         self.grant_permission(permission=permission_document_view)
         self.grant_permission(permission=permission_metadata_document_remove)
 
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             document_2 = self.document_type.new_document(
                 file_object=File(file_object)
             )
@@ -289,7 +289,7 @@ class DocumentMetadataTestCase(GenericDocumentViewTestCase):
         self.grant_permission(permission=permission_metadata_document_add)
         self.grant_permission(permission=permission_metadata_document_edit)
 
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_object:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_object:
             document_2 = self.document_type.new_document(
                 file_object=File(file_object)
             )
diff --git a/mayan/apps/sources/tests/test_views.py b/mayan/apps/sources/tests/test_views.py
index abe2490e8d..98c8cabc8c 100644
--- a/mayan/apps/sources/tests/test_views.py
+++ b/mayan/apps/sources/tests/test_views.py
@@ -142,7 +142,7 @@ class DocumentUploadIssueTestCase(GenericViewTestCase):
         self.assertEqual(WebFormSource.objects.count(), 1)
 
         # Upload the test document
-        with open(TEST_SMALL_DOCUMENT_PATH, 'rb') as file_descriptor:
+        with open(TEST_SMALL_DOCUMENT_PATH, mode='rb') as file_descriptor:
             self.post(
                 viewname='sources:upload_interactive', data={
                     'document-language': 'eng',