diff --git a/CHANGES.md b/CHANGES.md
index 165e1d4db4..cd23b8112b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,17 @@
+Synapse 1.4.1 (2019-10-18)
+==========================
+
+No changes since 1.4.1rc1.
+
+
+Synapse 1.4.1rc1 (2019-10-17)
+=============================
+
+Bugfixes
+--------
+
+- Fix bug where redacted events were sometimes incorrectly censored in the database, breaking APIs that attempted to fetch such events. ([\#6185](https://github.com/matrix-org/synapse/issues/6185), [5b0e9948](https://github.com/matrix-org/synapse/commit/5b0e9948eaae801643e594b5abc8ee4b10bd194e))
+
 Synapse 1.4.0 (2019-10-03)
 ==========================
 
diff --git a/debian/changelog b/debian/changelog
index 60c682cc57..02f2b508c2 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.4.1) stable; urgency=medium
+
+  * New synapse release 1.4.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Fri, 18 Oct 2019 10:13:27 +0100
+
 matrix-synapse-py3 (1.4.0) stable; urgency=medium
 
   * New synapse release 1.4.0.
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 2d52d26af5..a22567fcd5 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -35,4 +35,4 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.4.0"
+__version__ = "1.4.1"
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 2e485c8644..bb6ff0595a 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -23,7 +23,7 @@ from functools import wraps
 from six import iteritems, text_type
 from six.moves import range
 
-from canonicaljson import encode_canonical_json, json
+from canonicaljson import json
 from prometheus_client import Counter, Histogram
 
 from twisted.internet import defer
@@ -1632,9 +1632,7 @@ class EventsStore(
                 and original_event.internal_metadata.is_redacted()
             ):
                 # Redaction was allowed
-                pruned_json = encode_canonical_json(
-                    prune_event_dict(original_event.get_dict())
-                )
+                pruned_json = encode_json(prune_event_dict(original_event.get_dict()))
             else:
                 # Redaction wasn't allowed
                 pruned_json = None
diff --git a/synapse/storage/events_bg_updates.py b/synapse/storage/events_bg_updates.py
index 5717baf48c..e77a7e28af 100644
--- a/synapse/storage/events_bg_updates.py
+++ b/synapse/storage/events_bg_updates.py
@@ -71,6 +71,19 @@ class EventsBackgroundUpdatesStore(BackgroundUpdateStore):
             "redactions_received_ts", self._redactions_received_ts
         )
 
+        # This index gets deleted in `event_fix_redactions_bytes` update
+        self.register_background_index_update(
+            "event_fix_redactions_bytes_create_index",
+            index_name="redactions_censored_redacts",
+            table="redactions",
+            columns=["redacts"],
+            where_clause="have_censored",
+        )
+
+        self.register_background_update_handler(
+            "event_fix_redactions_bytes", self._event_fix_redactions_bytes
+        )
+
     @defer.inlineCallbacks
     def _background_reindex_fields_sender(self, progress, batch_size):
         target_min_stream_id = progress["target_min_stream_id_inclusive"]
@@ -458,3 +471,33 @@ class EventsBackgroundUpdatesStore(BackgroundUpdateStore):
             yield self._end_background_update("redactions_received_ts")
 
         return count
+
+    @defer.inlineCallbacks
+    def _event_fix_redactions_bytes(self, progress, batch_size):
+        """Undoes hex encoded censored redacted event JSON.
+        """
+
+        def _event_fix_redactions_bytes_txn(txn):
+            # This update is quite fast due to new index.
+            txn.execute(
+                """
+                UPDATE event_json
+                SET
+                    json = convert_from(json::bytea, 'utf8')
+                FROM redactions
+                WHERE
+                    redactions.have_censored
+                    AND event_json.event_id = redactions.redacts
+                    AND json NOT LIKE '{%';
+                """
+            )
+
+            txn.execute("DROP INDEX redactions_censored_redacts")
+
+        yield self.runInteraction(
+            "_event_fix_redactions_bytes", _event_fix_redactions_bytes_txn
+        )
+
+        yield self._end_background_update("event_fix_redactions_bytes")
+
+        return 1
diff --git a/synapse/storage/schema/delta/56/redaction_censor3_fix_update.sql.postgres b/synapse/storage/schema/delta/56/redaction_censor3_fix_update.sql.postgres
new file mode 100644
index 0000000000..67471f3ef5
--- /dev/null
+++ b/synapse/storage/schema/delta/56/redaction_censor3_fix_update.sql.postgres
@@ -0,0 +1,25 @@
+/* Copyright 2019 The Matrix.org Foundation C.I.C.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+-- There was a bug where we may have updated censored redactions as bytes,
+-- which can (somehow) cause json to be inserted hex encoded. These updates go
+-- and undoes any such hex encoded JSON.
+
+INSERT into background_updates (update_name, progress_json)
+  VALUES ('event_fix_redactions_bytes_create_index', '{}');
+
+INSERT into background_updates (update_name, progress_json, depends_on)
+  VALUES ('event_fix_redactions_bytes', '{}', 'event_fix_redactions_bytes_create_index');