diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 6cc96bbc5399..5d68796f7bc1 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -258,7 +258,6 @@ class GuestAccess:
 class ReceiptTypes:
     READ: Final = "m.read"
     READ_PRIVATE: Final = "m.read.private"
-    READ_PRIVATE_UNSTABLE: Final = "org.matrix.msc2285.read.private"
     FULLY_READ: Final = "m.fully_read"
 
 
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index e5c516695815..d2bdb9c8be79 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -203,27 +203,20 @@ def filter_out_private_receipts(
             for event_id, orig_event_content in room.get("content", {}).items():
                 event_content = orig_event_content
                 # If there are private read receipts, additional logic is necessary.
-                if (
-                    ReceiptTypes.READ_PRIVATE in event_content
-                    or ReceiptTypes.READ_PRIVATE_UNSTABLE in event_content
-                ):
+                if ReceiptTypes.READ_PRIVATE in event_content:
                     # Make a copy without private read receipts to avoid leaking
                     # other user's private read receipts..
                     event_content = {
                         receipt_type: receipt_value
                         for receipt_type, receipt_value in event_content.items()
-                        if receipt_type
-                        not in (
-                            ReceiptTypes.READ_PRIVATE,
-                            ReceiptTypes.READ_PRIVATE_UNSTABLE,
-                        )
+                        if receipt_type != ReceiptTypes.READ_PRIVATE
                     }
 
                     # Copy the current user's private read receipt from the
                     # original content, if it exists.
-                    user_private_read_receipt = orig_event_content.get(
-                        ReceiptTypes.READ_PRIVATE, {}
-                    ).get(user_id, None)
+                    user_private_read_receipt = orig_event_content[
+                        ReceiptTypes.READ_PRIVATE
+                    ].get(user_id, None)
                     if user_private_read_receipt:
                         event_content[ReceiptTypes.READ_PRIVATE] = {
                             user_id: user_private_read_receipt
diff --git a/synapse/storage/schema/main/delta/72/04remove_unstable_private_read_receipts.sql b/synapse/storage/schema/main/delta/72/04remove_unstable_private_read_receipts.sql
new file mode 100644
index 000000000000..409dc918d53d
--- /dev/null
+++ b/synapse/storage/schema/main/delta/72/04remove_unstable_private_read_receipts.sql
@@ -0,0 +1,17 @@
+/* Copyright 2022 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.
+ */
+
+DELETE FROM receipts_linearized WHERE receipt_type = 'org.matrix.msc2285.read.private';
+DELETE FROM receipts_graph WHERE receipt_type = 'org.matrix.msc2285.read.private';
diff --git a/tests/handlers/test_receipts.py b/tests/handlers/test_receipts.py
index 6fcbf20666b3..a95868b5c055 100644
--- a/tests/handlers/test_receipts.py
+++ b/tests/handlers/test_receipts.py
@@ -296,26 +296,6 @@ def test_leaves_our_private_and_their_public(self):
             ],
         )
 
-    def test_filters_out_unstable_private_receipt(self):
-        self._test_filters_private(
-            [
-                {
-                    "content": {
-                        "$1435641916114394fHBLK:matrix.org": {
-                            "org.matrix.msc2285.read.private": {
-                                "@rikj:jki.re": {
-                                    "ts": 1436451550453,
-                                }
-                            }
-                        }
-                    },
-                    "room_id": "!jEsUZKDJdhlrceRyVU:example.org",
-                    "type": EduTypes.RECEIPT,
-                }
-            ],
-            [],
-        )
-
     def test_we_do_not_mutate(self):
         """Ensure the input values are not modified."""
         events = [