diff --git a/lofar_stingray/streams/_zmq.py b/lofar_stingray/streams/_zmq.py
index f4959377726d5c11ef2e68b4d26c74f1866a8d79..0f6f1d4e4dce49b19952a836d5ba358bce3f7dbf 100644
--- a/lofar_stingray/streams/_zmq.py
+++ b/lofar_stingray/streams/_zmq.py
@@ -29,17 +29,6 @@ class ZeroMQReceiver(ZeroMQSubscriber):
 
         self.num_bytes_read = 0
 
-    def open(self):
-        """Open I/O resources"""
-
-    def __enter__(self):
-        self.open()
-        return self
-
-    def __exit__(self, type_, value, exc):
-        self.close()
-        return False
-
     def __iter__(self):
         """Iterates over all packets in the stream."""
         return self
diff --git a/requirements.txt b/requirements.txt
index 872d79b1bf4df5e4aa9869fdfef6fe598753f6c4..67394cf5f677689a395ad7df17833cf703697ab3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 numpy
 minio~=7.1.17
-lofar-station-client>=0.20 # Apache 2
+lofar-station-client>=0.21 # Apache 2
 setuptools~=68.2.0
 logfmter # MIT
 prometheus-client # Apache 2
diff --git a/tests/streams/test_zmq.py b/tests/streams/test_zmq.py
index 7813ad70edeefbf5665a7638aa93e0048276a0eb..e5fd7dec518f96ab3ea0d891afdf48ed5aa04687 100644
--- a/tests/streams/test_zmq.py
+++ b/tests/streams/test_zmq.py
@@ -21,8 +21,8 @@ class TestZeroMQReceiver(TestCase):
         ctx.return_value = mock.Mock()
         ctx.return_value.socket.return_value = socket_mock
         socket_mock.recv_multipart.side_effect = [
-            ["test".encode(), "2024-05-17T08:35:48Z".encode(), "data1".encode()],
-            ["test".encode(), "2024-05-17T08:36:48Z".encode(), "data2".encode()],
+            ["test".encode(), "2024-05-17T08:35:48".encode(), "data1".encode()],
+            ["test".encode(), "2024-05-17T08:36:48".encode(), "data2".encode()],
             zmq.ZMQError(errno=zmq.ETERM),
         ]