From baf8948eb5b3be04f06bba0fce87153834bda16f Mon Sep 17 00:00:00 2001
From: Travis Ralston <travpc@gmail.com>
Date: Sun, 24 Feb 2019 21:53:50 -0700
Subject: [PATCH 1/2] Describe M_UNSUPPORTED_ROOM_VERSION on invite and
 createRoom endpoints

Spec for MSC1866: https://github.com/matrix-org/matrix-doc/pull/1866
---
 api/client-server/create_room.yaml                 |  6 ++++++
 api/client-server/inviting.yaml                    | 14 ++++++++++++++
 .../client_server/newsfragments/1903.feature       |  1 +
 3 files changed, 21 insertions(+)
 create mode 100644 changelogs/client_server/newsfragments/1903.feature

diff --git a/api/client-server/create_room.yaml b/api/client-server/create_room.yaml
index d361d9738..bce61aad3 100644
--- a/api/client-server/create_room.yaml
+++ b/api/client-server/create_room.yaml
@@ -244,6 +244,12 @@ paths:
               invalid: for example, the user's ``power_level`` is set below
               that necessary to set the room name (``errcode`` set to
               ``M_INVALID_ROOM_STATE``).
+
+            - The homeserver doesn't support the requested room version, or
+              one or more users being invited to the new room are residents
+              of a homeserver which does not support the requested room version.
+              The ``errcode`` will be ``M_UNSUPPORTED_ROOM_VERSION`` in these
+              cases.
           schema:
             "$ref": "definitions/errors/error.yaml"
       tags:
diff --git a/api/client-server/inviting.yaml b/api/client-server/inviting.yaml
index f312d5ceb..dfa66b9b0 100644
--- a/api/client-server/inviting.yaml
+++ b/api/client-server/inviting.yaml
@@ -82,6 +82,20 @@ paths:
               }
           schema:
             type: object
+        400:
+          description: |-
+
+            The request is invalid. A meaningful ``errcode`` and description
+            error text will be returned. Example reasons for rejection include:
+
+            - The request body is malformed (``errcode`` set to ``M_BAD_JSON``
+              or ``M_NOT_JSON``).
+
+            - One or more users being invited to the room are residents of a
+              homeserver which does not support the requested room version. The
+              ``errcode`` will be ``M_UNSUPPORTED_ROOM_VERSION`` in these cases.
+          schema:
+            "$ref": "definitions/errors/error.yaml"
         403:
           description: |-
             You do not have permission to invite the user to the room. A meaningful ``errcode`` and description error text will be returned. Example reasons for rejections are:
diff --git a/changelogs/client_server/newsfragments/1903.feature b/changelogs/client_server/newsfragments/1903.feature
new file mode 100644
index 000000000..1c64d826e
--- /dev/null
+++ b/changelogs/client_server/newsfragments/1903.feature
@@ -0,0 +1 @@
+Emit ``M_UNSUPPORTED_ROOM_VERSION`` error codes where applicable on ``/createRoom`` and ``/invite`` APIs.

From adb721bc0b101bcf458a17275792eec20fe96e63 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travpc@gmail.com>
Date: Sun, 24 Feb 2019 21:55:57 -0700
Subject: [PATCH 2/2] Fix unrelated changelog entry's RST representation

---
 changelogs/client_server/newsfragments/1874.feature | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/changelogs/client_server/newsfragments/1874.feature b/changelogs/client_server/newsfragments/1874.feature
index 03b891e25..bdab54644 100644
--- a/changelogs/client_server/newsfragments/1874.feature
+++ b/changelogs/client_server/newsfragments/1874.feature
@@ -1 +1 @@
-Add `M_RESOURCE_LIMIT_EXCEEDED` as an error code for when homeservers exceed limits imposed on them.
+Add ``M_RESOURCE_LIMIT_EXCEEDED`` as an error code for when homeservers exceed limits imposed on them.