diff --git a/README.md b/README.md
index d657672..7b792b4 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ The [OpenRefine Python Client from PaulMakepeace](https://github.com/PaulMakepea
 This fork extends the command line interface (CLI) and is distributed as a convenient one-file-executable (Windows, Linux, macOS).
 It is also available via Docker Hub, PyPI and Binder.
 
-works with OpenRefine 2.7, 2.8, 3.0, 3.1, 3.2
+works with OpenRefine 2.7, 2.8, 3.0, 3.1, 3.2, 3.3, 3.4, 3.4.1
 
 ## Download
 
@@ -714,7 +714,7 @@ Note to myself: When releasing a new version...
 4. Run functional tests with Linux executable
 
    ```sh
-   for v in 2.7 2.8 3.0 3.1 3.2; do
+   for v in 2.7 2.8 3.0 3.1 3.2 3.3 3.4 3.4.1; do
       ./tests-cli.sh $v openrefine-client_0-3-7_linux
    done
    ```
diff --git a/google/refine/refine.py b/google/refine/refine.py
index 0955764..0eec753 100644
--- a/google/refine/refine.py
+++ b/google/refine/refine.py
@@ -53,6 +53,18 @@ class RefineServer(object):
             server = self.url()
         self.server = server[:-1] if server.endswith('/') else server
         self.__version = None     # see version @property below
+        self.token = None         # CSRF token introduced in OpenRefine 3.3
+        self.get_csrf_token()
+
+    def get_csrf_token(self):
+        """Return csrf token."""
+        try:
+            url = self.server + '/command/core/get-csrf-token'
+            response = json.loads(urllib2.urlopen(url).read())
+            self.token = response['token']
+            return self.token
+        except:
+            pass # fail silently to not disturb usage of OpenRefine <3.3
 
     def urlopen(self, command, data=None, params=None, project_id=None):
         """Open a Refine URL and with optional query params and POST data.
@@ -73,6 +85,9 @@ class RefineServer(object):
                 data['project'] = project_id
             else:
                 params['project'] = project_id
+        # be lazy and send the token for each API call (even when not needed)
+        if self.token:
+            params['csrf_token'] = self.token
         if params:
             url += '?' + urllib.urlencode(params)
         req = urllib2.Request(url)