diff --git a/taiga/projects/occ/mixins.py b/taiga/projects/occ/mixins.py
index 27b8e78a..777a59b4 100644
--- a/taiga/projects/occ/mixins.py
+++ b/taiga/projects/occ/mixins.py
@@ -37,7 +37,9 @@ class OCCResourceMixin(object):
         return param_version
 
     def _validate_param_version(self, param_version, current_version):
-        if param_version is not None:
+        if param_version is None:
+            return False
+        else:
             if param_version < 0:
                 return False
             if current_version is not None and param_version > current_version:
@@ -50,28 +52,27 @@ class OCCResourceMixin(object):
         if obj.id:
             current_version = type(obj).objects.model.objects.get(id=obj.id).version
 
-        # Extract param version
-        param_version = self._extract_param_version()
-        if not self._validate_param_version(param_version, current_version):
-            raise exc.WrongArguments({"version": _("The version is not valid")})
+            # Extract param version
+            param_version = self._extract_param_version()
+            if not self._validate_param_version(param_version, current_version):
+                raise exc.WrongArguments({"version": _("The version parameter is not valid")})
 
-        if current_version != param_version:
-            diff_versions = current_version - param_version
+            if current_version != param_version:
+                diff_versions = current_version - param_version
 
-            modifying_fields = set(self.request.DATA.keys())
-            if "version" in modifying_fields:
-                modifying_fields.remove("version")
+                modifying_fields = set(self.request.DATA.keys())
+                if "version" in modifying_fields:
+                    modifying_fields.remove("version")
 
-            modified_fields = set(get_modified_fields(obj, diff_versions))
-            if "version" in modifying_fields:
-                modified_fields.remove("version")
+                modified_fields = set(get_modified_fields(obj, diff_versions))
+                if "version" in modifying_fields:
+                    modified_fields.remove("version")
 
-            both_modified = modifying_fields & modified_fields
+                both_modified = modifying_fields & modified_fields
 
-            if both_modified:
-                raise exc.WrongArguments({"version": _("The version doesn't match with the current one")})
+                if both_modified:
+                    raise exc.WrongArguments({"version": _("The version doesn't match with the current one")})
 
-        if obj.id:
             obj.version = models.F('version') + 1
 
     def pre_save(self, obj):
diff --git a/tests/integration/test_occ.py b/tests/integration/test_occ.py
index 0e6eb974..9826cf0e 100644
--- a/tests/integration/test_occ.py
+++ b/tests/integration/test_occ.py
@@ -333,3 +333,26 @@ def test_valid_concurrent_save_for_task_different_fields(client):
         data = {"version": 1, "description": "test 2"}
         response = client.patch(url, json.dumps(data), content_type="application/json")
         assert response.status_code == 200
+
+
+
+def test_invalid_save_without_version_parameter(client):
+    user = f.UserFactory.create()
+    project = f.ProjectFactory.create(owner=user)
+    f.MembershipFactory.create(project=project, user=user, is_owner=True)
+    client.login(user)
+
+    mock_path = "taiga.projects.tasks.api.TaskViewSet.pre_conditions_on_save"
+    with patch(mock_path):
+        url = reverse("tasks-list")
+        data = {"subject": "test",
+                "project": project.id,
+                "status": f.TaskStatusFactory.create(project=project).id}
+        response = client.json.post(url, json.dumps(data))
+        assert response.status_code == 201
+
+        task_id = json.loads(response.content)["id"]
+        url = reverse("tasks-detail", args=(task_id,))
+        data = {"subject": "test 1"}
+        response = client.patch(url, json.dumps(data), content_type="application/json")
+        assert response.status_code == 400