From b85f494ff459f2b670d4335b1f6cc22e8a287d56 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travisr@matrix.org>
Date: Wed, 24 May 2023 17:32:07 -0600
Subject: [PATCH 1/2] Add MSC3820 opt2 unstable room version

MSC: https://github.com/matrix-org/matrix-spec-proposals/pull/3820

There are no tests for this because the MSCs involved should already be tested, and when v11 is accepted there might be different test cases. Instead, it's suggested that tests get moved/created when v11 becomes stable.
---
 synapse/api/room_versions.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index 7030b133d3a6..035a14171bdb 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -485,6 +485,30 @@ class RoomVersions:
         msc3931_push_features=(),
         msc3989_redaction_rules=True,
     )
+    MSC3820opt2 = RoomVersion(
+        # Based upon v10
+        "org.matrix.msc3820.opt2",
+        RoomDisposition.UNSTABLE,
+        EventFormatVersions.ROOM_V4_PLUS,
+        StateResolutionVersions.V2,
+        enforce_key_validity=True,
+        special_case_aliases_auth=False,
+        strict_canonicaljson=True,
+        limit_notifications_power_levels=True,
+        msc2175_implicit_room_creator=True,  # Used by MSC3820
+        msc2176_redaction_rules=True,  # Used by MSC3820
+        msc3083_join_rules=True,
+        msc3375_redaction_rules=True,
+        msc2403_knocking=True,
+        msc2716_historical=False,
+        msc2716_redactions=False,
+        msc3389_relation_redactions=False,
+        msc3787_knock_restricted_join_rule=True,
+        msc3667_int_only_power_levels=True,
+        msc3821_redaction_rules=True,  # Used by MSC3820
+        msc3931_push_features=(),
+        msc3989_redaction_rules=True,  # Used by MSC3820
+    )
 
 
 KNOWN_ROOM_VERSIONS: Dict[str, RoomVersion] = {

From 518c7ede56890e106ae28b0fca81bceb14eea34d Mon Sep 17 00:00:00 2001
From: Travis Ralston <travisr@matrix.org>
Date: Wed, 24 May 2023 17:34:06 -0600
Subject: [PATCH 2/2] changelog

---
 changelog.d/15666.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/15666.misc

diff --git a/changelog.d/15666.misc b/changelog.d/15666.misc
new file mode 100644
index 000000000000..92eae499524b
--- /dev/null
+++ b/changelog.d/15666.misc
@@ -0,0 +1 @@
+Implement "option 2" for [MSC3820](https://github.com/matrix-org/matrix-spec-proposals/pull/3820): Room version 11.
\ No newline at end of file