diff --git a/pisa/responder.py b/pisa/responder.py
index dbfac15..89b1096 100644
--- a/pisa/responder.py
+++ b/pisa/responder.py
@@ -126,9 +126,9 @@ class Responder:
             has missed. Used to trigger rebroadcast if needed.
         asleep (:obj:`bool`): A flag that signals whether the :obj:`Responder` is asleep or awake.
         block_queue (:obj:`Queue`): A queue used by the :obj:`Responder` to receive block hashes from ``bitcoind``. It
-            is populated by the :obj:`ZMQSubscriber <pisa.utils.zmq_subscriber.ZMQSubscriber>`.
-        zmq_subscriber (:obj:`ZMQSubscriber <pisa.utils.zmq_subscriber.ZMQSubscriber>`): a ``ZMQSubscriber`` instance
-            used to receive new block notifications from ``bitcoind``.
+            is populated by the :obj:`ChainMonitor <pisa.chain_monitor.ChainMonitor>`.
+        chain_monitor (:obj:`ChainMonitor <pisa.chain_monitor.ChainMonitor>`): a ``ChainMonitor`` instance used to track
+            new blocks received by ``bitcoind``.
         db_manager (:obj:`DBManager <pisa.db_manager.DBManager>`): A ``DBManager`` instance to interact with the
             database.
 
@@ -223,8 +223,7 @@ class Responder:
         The :obj:`TransactionTracker` is stored in ``trackers`` and ``tx_tracker_map`` and the ``penalty_txid`` added to
         ``unconfirmed_txs`` if ``confirmations=0``. Finally, the data is also stored in the database.
 
-        ``add_tracker`` awakes the :obj:`Responder` and creates a connection with the
-        :obj:`ZMQSubscriber <pisa.utils.zmq_subscriber.ZMQSubscriber>` if he is asleep.
+        ``add_tracker`` awakes the :obj:`Responder` if it is asleep.
 
         Args:
             uuid (:obj:`str`): a unique identifier for the appointment.
diff --git a/pisa/watcher.py b/pisa/watcher.py
index 1da5c75..079953b 100644
--- a/pisa/watcher.py
+++ b/pisa/watcher.py
@@ -27,7 +27,7 @@ class Watcher:
     If an appointment reaches its end with no breach, the data is simply deleted.
 
     The :class:`Watcher` receives information about new received blocks via the ``block_queue`` that is populated by the
-    :obj:`ZMQSubscriber <pisa.utils.zmq_subscriber>`.
+    :obj:`ChainMonitor <pisa.chain_monitor.ChainMonitor>`.
 
     Args:
         db_manager (:obj:`DBManager <pisa.db_manager>`): a ``DBManager`` instance to interact with the database.
@@ -45,11 +45,11 @@ class Watcher:
             appointments with the same ``locator``.
         asleep (:obj:`bool`): A flag that signals whether the :obj:`Watcher` is asleep or awake.
         block_queue (:obj:`Queue`): A queue used by the :obj:`Watcher` to receive block hashes from ``bitcoind``. It is
-            populated by the :obj:`ZMQSubscriber <pisa.utils.zmq_subscriber.ZMQSubscriber>`.
+        populated by the :obj:`ChainMonitor <pisa.chain_monitor.ChainMonitor>`.
         max_appointments(:obj:`int`): the maximum amount of appointments that the :obj:`Watcher` will keep at any given
             time.
-        zmq_subscriber (:obj:`ZMQSubscriber <pisa.utils.zmq_subscriber.ZMQSubscriber>`): a ZMQSubscriber instance used
-            to receive new block notifications from ``bitcoind``.
+        chain_monitor (:obj:`ChainMonitor <pisa.chain_monitor.ChainMonitor>`): a ``ChainMonitor`` instance used to track
+            new blocks received by ``bitcoind``.
         db_manager (:obj:`DBManager <pisa.db_manager>`): A db manager instance to interact with the database.
 
     Raises:
diff --git a/test/pisa/unit/test_responder.py b/test/pisa/unit/test_responder.py
index b3e339e..d515ff7 100644
--- a/test/pisa/unit/test_responder.py
+++ b/test/pisa/unit/test_responder.py
@@ -195,7 +195,7 @@ def test_add_bad_response(responder):
     tracker = create_dummy_tracker()
 
     # Now that the asleep / awake functionality has been tested we can avoid manually killing the responder by setting
-    # to awake. That will prevent the zmq thread to be launched again.
+    # to awake. That will prevent the chain_monitor thread to be launched again.
     responder.asleep = False
 
     # A txid instead of a rawtx should be enough for unit tests using the bitcoind mock, better tests are needed though.