matrix-spec/content/rooms/v11.md

---
title: Room Version 11
type: docs
weight: 100
---

This room version builds on [version 10](/rooms/v10) while clarifying redaction
rules.

## Client considerations

### Redactions

{{< added-in this=true >}} The top-level `origin`, `membership`, and `prev_state` properties
are no longer protected from redaction. The [`m.room.create`](/client-server-api#mroomcreate)
event now keeps the entire `content` property. The [`m.room.redaction`](/client-server-api#mroomredaction)
event keeps the `redacts` property under `content`. The
[`m.room.power_levels`](/client-server-api#mroompower_levels) event keeps the
`invite` property under `content`.

The full redaction algorithm follows.

{{% rver-fragment name="v11-redactions" withVersioning="true" %}}

### Event format

Clients should no longer depend on the `creator` property in the `content` of
[`m.room.create`](/client-server-api#mroomcreate) events.  In all room versions,
clients can rely on `sender` instead to determine a room creator.

The format of [`m.room.redaction`](/client-server-api#mroomredaction)
events has been modified. Client should look for the `redacts` key under `content`
instead of a top-level event property.

The `third_party_invite` key of [`m.room.member`](/client-server-api#mroommember)
events is no longer redacted, *but* will only contain the `signed` key after redaction.

## Server implementation components

{{% boxes/warning %}}
The information contained in this section is strictly for server
implementors. Applications which use the Client-Server API are generally
unaffected by the intricacies contained here. The section above
regarding client considerations is the resource that Client-Server API
use cases should reference.
{{% /boxes/warning %}}

This room version updates the redaction algorithm and modifies how servers should
create `m.room.create` and `m.room.redaction` events.

Room version 11 is based upon room version 10 with the following considerations.

### Redactions

[See above](#redactions).

### Event format

The core event format is the same as [room version 10](/rooms/v10#event-format).
However, this room version changes some properties of some event types.

{{% rver-fragment name="v11-event-format" %}}

#### Remove the `creator` property of `m.room.create` events

The `content` of a `m.room.create` event no longer has a `creator` property,
which previously was always equivalent to the `sender` of the event.

#### Moving the `redacts` property of `m.room.redaction` events to a `content` property

The `redacts` property of `m.room.redaction` events is moved from a top-level
event property to a property under the event `content`.

For backwards-compatibility with older clients, servers should add a `redacts` property
to the top level of `m.room.redaction` events in when serving such events over the
Client-Server API.

For improved compatibility with newer clients, servers should add a `redacts` property
to the `content` of `m.room.redaction` events in *older* room versions when serving
such events over the Client-Server API.

### Authorization rules

Events must be signed by the server denoted by the `sender` property.

`m.room.redaction` events are not explicitly part of the auth rules.
They are still subject to the minimum power level rules, but should always
fall into "10. Otherwise, allow". Instead of being authorized at the time
of receipt, they are authorized at a later stage: see the
[Redactions](#redactions) section below for more information.

The types of state events that affect authorization are:

-   [`m.room.create`](/client-server-api#mroomcreate)
-   [`m.room.member`](/client-server-api#mroommember)
-   [`m.room.join_rules`](/client-server-api#mroomjoin_rules)
-   [`m.room.power_levels`](/client-server-api#mroompower_levels)
-   [`m.room.third_party_invite`](/client-server-api#mroomthird_party_invite)

{{% boxes/note %}}
Power levels are inferred from defaults when not explicitly supplied.
For example, mentions of the `sender`'s power level can also refer to
the default power level for users in the room.
{{% /boxes/note %}}

The rules are as follows:

1.  {{< changed-in this="true" >}}
    If type is `m.room.create`:
    1.  If it has any `prev_events`, reject.
    2.  If the domain of the `room_id` does not match the domain of the
        `sender`, reject.
    3.  If `content.room_version` is present and is not a recognised
        version, reject.
    4.  Otherwise, allow.
2.  Considering the event's `auth_events`:
    1.  If there are duplicate entries for a given `type` and `state_key` pair,
        reject.
    2.  If there are entries whose `type` and `state_key` don't match those
        specified by the [auth events
        selection](/server-server-api#auth-events-selection)
        algorithm described in the server specification, reject.
    3.  If there are entries which were themselves rejected under the [checks
        performed on receipt of a
        PDU](/server-server-api/#checks-performed-on-receipt-of-a-pdu), reject.
    4. If there is no `m.room.create` event among the entries, reject.
3. If the `content` of the `m.room.create` event in the room state has the
   property `m.federate` set to `false`, and the `sender` domain of the event
   does not match the `sender` domain of the create event, reject.
4.  If type is `m.room.member`:
    1.  If there is no `state_key` property, or no `membership` property in
        `content`, reject.
    2.  If `content` has a `join_authorised_via_users_server`
        key:
        1.  If the event is not validly signed by the homeserver of the user ID denoted
            by the key, reject.
    3.  If `membership` is `join`:
        1.  {{< changed-in this="true" >}}
            If the only previous event is an `m.room.create` and the
            `state_key` is the sender, allow.
        2.  If the `sender` does not match `state_key`, reject.
        3.  If the `sender` is banned, reject.
        4.  If the `join_rule` is `invite` or `knock` then allow if
            membership state is `invite` or `join`.
        5.  If the `join_rule` is `restricted` or `knock_restricted`:
            1.  If membership state is `join` or `invite`, allow.
            2.  If the `join_authorised_via_users_server` key in `content`
                is not a user with sufficient permission to invite other
                users, reject.
            3.  Otherwise, allow.
        6.  If the `join_rule` is `public`, allow.
        7.  Otherwise, reject.
    4.  If `membership` is `invite`:
        1.  If `content` has a `third_party_invite` property:
            1.  If *target user* is banned, reject.
            2.  If `content.third_party_invite` does not have a `signed`
                property, reject.
            3.  If `signed` does not have `mxid` and `token` properties,
                reject.
            4.  If `mxid` does not match `state_key`, reject.
            5.  If there is no `m.room.third_party_invite` event in the
                current room state with `state_key` matching `token`,
                reject.
            6.  If `sender` does not match `sender` of the
                `m.room.third_party_invite`, reject.
            7.  If any signature in `signed` matches any public key in
                the `m.room.third_party_invite` event, allow. The public
                keys are in `content` of `m.room.third_party_invite` as:
                1.  A single public key in the `public_key` property.
                2.  A list of public keys in the `public_keys` property.
            8.  Otherwise, reject.
        2.  If the `sender`'s current membership state is not `join`,
            reject.
        3.  If *target user*'s current membership state is `join` or
            `ban`, reject.
        4.  If the `sender`'s power level is greater than or equal to
            the *invite level*, allow.
        5.  Otherwise, reject.
    5.  If `membership` is `leave`:
        1.  If the `sender` matches `state_key`, allow if and only if
            that user's current membership state is `invite`, `join`,
            or `knock`.
        2.  If the `sender`'s current membership state is not `join`,
            reject.
        3.  If the *target user*'s current membership state is `ban`,
            and the `sender`'s power level is less than the *ban level*,
            reject.
        4.  If the `sender`'s power level is greater than or equal to
            the *kick level*, and the *target user*'s power level is
            less than the `sender`'s power level, allow.
        5.  Otherwise, reject.
    6.  If `membership` is `ban`:
        1.  If the `sender`'s current membership state is not `join`,
            reject.
        2.  If the `sender`'s power level is greater than or equal to
            the *ban level*, and the *target user*'s power level is less
            than the `sender`'s power level, allow.
        3.  Otherwise, reject.
    7. If `membership` is `knock`:
        1.  If the `join_rule` is anything other than `knock` or
            `knock_restricted`, reject.
        2.  If `sender` does not match `state_key`, reject.
        3.  If the `sender`'s current membership is not `ban`, `invite`,
            or `join`, allow.
        4.  Otherwise, reject.
    8.  Otherwise, the membership is unknown. Reject.
5.  If the `sender`'s current membership state is not `join`, reject.
6.  If type is `m.room.third_party_invite`:
    1.  Allow if and only if `sender`'s current power level is greater
        than or equal to the *invite level*.
7.  If the event type's *required power level* is greater than the
    `sender`'s power level, reject.
8.  If the event has a `state_key` that starts with an `@` and does not
    match the `sender`, reject.
9. If type is `m.room.power_levels`:
    1.  If any of the properties `users_default`, `events_default`, `state_default`,
        `ban`, `redact`, `kick`, or `invite` in `content` are present and
        not an integer, reject.
    2.  If either of the properties `events` or `notifications` in `content`
        are present and not an object with values that are integers,
        reject.
    3.  If the `users` property in `content` is not an obiect with keys that
        are valid user IDs with values that are integers, reject.
    4.  If there is no previous `m.room.power_levels` event in the room,
        allow.
    5.  For the properties `users_default`, `events_default`, `state_default`,
        `ban`, `redact`, `kick`, `invite` check if they were added,
        changed or removed. For each found alteration:
        1.  If the current value is higher than the `sender`'s current
            power level, reject.
        2.  If the new value is higher than the `sender`'s current power
            level, reject.
    6.  For each entry being changed in, or removed from, the `events` or
        `notifications` properties:
        1.  If the current value is greater than the `sender`'s current
            power level, reject.
    7.  For each entry being added to, or changed in, the `events` or
        `notifications` properties:
        1.  If the new value is greater than the `sender`'s current power
            level, reject.
    8.  For each entry being changed in, or removed from, the `users` property,
        other than the `sender`'s own entry:
        1.  If the current value is greater than or equal to the `sender`'s
            current power level, reject.
    9.  For each entry being added to, or changed in, the `users` property:
        1.  If the new value is greater than the `sender`'s current power
            level, reject.
    10. Otherwise, allow.
10. Otherwise, allow.

{{% boxes/note %}}
Some consequences of these rules:

-   Unless you are a member of the room, the only permitted operations
    (apart from the initial create/join) are: joining a public room;
    accepting or rejecting an invitation to a room.
-   To unban somebody, you must have power level greater than or equal
    to both the kick *and* ban levels, *and* greater than the target
    user's power level.
{{% /boxes/note %}}

## Unchanged from v10

The following sections have not been modified since v10, but are included for
completeness.

### Handling redactions

{{% rver-fragment name="v3-handling-redactions" %}}

### Event IDs

{{% rver-fragment name="v4-event-ids" %}}

### State resolution

{{% rver-fragment name="v2-state-res" %}}

### Canonical JSON

{{% rver-fragment name="v6-canonical-json" %}}

### Signing key validity period

{{% rver-fragment name="v5-signing-requirements" %}}