diff --git a/lib/Protocol/Matrix.pm b/lib/Protocol/Matrix.pm
index b301e50ba..eb0316a02 100644
--- a/lib/Protocol/Matrix.pm
+++ b/lib/Protocol/Matrix.pm
@@ -266,11 +266,13 @@ my %ALLOWED_CONTENT_BY_TYPE = (
 
 sub redact_event
 {
-   my ( $event ) = @_;
+   my ( $event, $room_version ) = @_;
+   $room_version //= 1;
 
    defined( my $type = $event->{type} ) or
       croak "Event requires a 'type'";
 
+   delete $event->{redacts};
    my $old_content = delete $event->{content};
    my $old_unsigned = delete $event->{unsigned};
 
@@ -278,6 +280,36 @@ sub redact_event
 
    my $new_content = $event->{content} = {};
 
+   $old_content  //= {};
+   $old_unsigned //= {};
+
+   # Room version 11+ uses updated redaction rules:
+   # - m.room.create: entire content property is preserved
+   # - m.room.power_levels: 'invite' is also preserved
+   # - m.room.member: 'third_party_invite.signed' is also preserved
+   # - m.room.redaction: 'redacts' is also preserved
+   # Non-numeric (unstable) room versions are assumed to be 11+
+   if( $room_version !~ /\A[0-9]+\z/ or $room_version >= 11 ) {
+      if( $type eq 'm.room.create' ) {
+         %$new_content = %$old_content;
+         $event->{unsigned}{age_ts} = $old_unsigned->{age_ts} if exists $old_unsigned->{age_ts};
+         return;
+      }
+      if( $type eq 'm.room.power_levels' ) {
+         $new_content->{invite} = $old_content->{invite} if exists $old_content->{invite};
+      }
+      if( $type eq 'm.room.member' ) {
+         my $tpi = $old_content->{third_party_invite};
+         if( ref $tpi eq 'HASH' && exists $tpi->{signed} ) {
+            $new_content->{third_party_invite} = { signed => $tpi->{signed} };
+         }
+      }
+      if( $type eq 'm.room.redaction' ) {
+         # In v11, 'redacts' moved into content; preserve content.redacts
+         $new_content->{redacts} = $old_content->{redacts} if exists $old_content->{redacts};
+      }
+   }
+
    if( my $allowed_content_keys = $ALLOWED_CONTENT_BY_TYPE{$type} ) {
       exists $old_content->{$_} and $new_content->{$_} = $old_content->{$_} for
          @$allowed_content_keys;
@@ -288,8 +320,8 @@ sub redact_event
 
 sub redacted_event
 {
-   my ( $event ) = @_;
-   redact_event( $event = { %$event } );
+   my ( $event, $room_version ) = @_;
+   redact_event( $event = { %$event }, $room_version );
    return $event;
 }
 
@@ -309,6 +341,7 @@ sub sign_event_json
 
    my $origin = $args{origin} or croak "Require an 'origin'";
    my $key_id = $args{key_id} or croak "Require a 'key_id'";
+   my $room_version = delete $args{room_version};
 
    # 'hashes' records the original unredacted version
    {
@@ -319,7 +352,7 @@ sub sign_event_json
    }
 
    # Signature is of redacted version
-   sign_json( my $signed = redacted_event( $event ), %args );
+   sign_json( my $signed = redacted_event( $event, $room_version ), %args );
 
    $event->{signatures} = $signed->{signatures};
 }
@@ -349,9 +382,10 @@ sub signed_event_json
 
 sub verify_event_json_signature
 {
-   my ( $event, @args ) = @_;
+   my ( $event, %args ) = @_;
 
-   verify_json_signature( redacted_event( $event ), @args );
+   my $room_version = delete $args{room_version};
+   verify_json_signature( redacted_event( $event, $room_version ), %args );
 }
 
 =head1 AUTHOR
diff --git a/lib/SyTest/Federation/AuthChecks.pm b/lib/SyTest/Federation/AuthChecks.pm
index 52c9cad78..ec8091445 100644
--- a/lib/SyTest/Federation/AuthChecks.pm
+++ b/lib/SyTest/Federation/AuthChecks.pm
@@ -48,9 +48,12 @@ sub auth_check_event
          $accepted_events, $event->{auth_events}, "m.room.create"
       );
 
+      my $room_creator = _creator_for_create_event( $create_event );
+      return 0 unless defined $room_creator;
+
       {
          users => {
-            $create_event->{content}{creator} => 100,
+            $room_creator => 100,
          },
          users_default => 0,
 
@@ -86,6 +89,35 @@ sub auth_check_event
    return 1;
 }
 
+=head2 _creator_for_create_event
+
+   my $creator = _creator_for_create_event( $create_event )
+
+Returns the creator MXID for a given C<m.room.create> event. For room
+version 11+, the creator is taken from the C<sender> field; for older
+versions it is taken from C<content.creator>.
+
+=cut
+
+sub _creator_for_create_event
+{
+   my ( $create_event ) = @_;
+
+   $create_event or
+      return undef;
+
+   my $room_version = $create_event->{content}{room_version};
+
+   # For room version 11+ (or unstable/non-numeric versions), 'creator' is absent
+   # from content; use sender instead.
+   if( defined $room_version && ( $room_version !~ /\A[0-9]+\z/ || $room_version >= 11 ) ) {
+      return $create_event->{sender};
+   }
+
+   # For older room versions, 'creator' must be present explicitly.
+   return $create_event->{content}{creator};
+}
+
 sub auth_check_event_m_room_create
 {
    my $self = shift;
@@ -96,7 +128,8 @@ sub auth_check_event_m_room_create
       return 0;
 
    # Any m.room.create event is acceptable, provided that the creator matches
-   return $event->{sender} eq $event->{content}{creator};
+   my $creator = _creator_for_create_event( $event );
+   return defined( $creator ) and $event->{sender} eq $creator;
 }
 
 sub auth_check_event_m_room_member
@@ -117,7 +150,8 @@ sub auth_check_event_m_room_member
       $accepted_events, $event->{auth_events}, "m.room.create"
    );
 
-   if( $create_event and $event->{state_key} eq $create_event->{content}{creator} ) {
+   my $creator = _creator_for_create_event( $create_event );
+   if( $creator and $event->{state_key} eq $creator ) {
       return 1;
    }
 
diff --git a/lib/SyTest/Federation/Datastore.pm b/lib/SyTest/Federation/Datastore.pm
index 6f6d4e0bd..0cab891dc 100644
--- a/lib/SyTest/Federation/Datastore.pm
+++ b/lib/SyTest/Federation/Datastore.pm
@@ -77,12 +77,13 @@ the C<signatures> key.
 sub sign_event
 {
    my $self = shift;
-   my ( $event ) = @_;
+   my ( $event, %args ) = @_;
 
    sign_event_json( $event,
-      secret_key => $self->secret_key,
-      origin     => $self->server_name,
-      key_id     => $self->key_id,
+      secret_key   => $self->secret_key,
+      origin       => $self->server_name,
+      key_id       => $self->key_id,
+      room_version => $args{room_version},
    );
 }
 
@@ -204,12 +205,12 @@ sub create_event
          $event_id = $self->next_event_id( $event_id_suffix );
          $event->{event_id} = $event_id;
       }
-      $self->sign_event( $event );
+      $self->sign_event( $event, room_version => $room_version );
    } else {
       die "event with explicit event_id in room v$room_version"
          if defined $event_id;
 
-      $self->sign_event( $event );
+      $self->sign_event( $event, room_version => $room_version );
       $event_id = id_for_event( $event, $room_version );
    }
 
diff --git a/lib/SyTest/Federation/Protocol.pm b/lib/SyTest/Federation/Protocol.pm
index 1f8daf2af..36c5d852f 100644
--- a/lib/SyTest/Federation/Protocol.pm
+++ b/lib/SyTest/Federation/Protocol.pm
@@ -44,9 +44,10 @@ Calculates the reference hash of an event.
 
 sub hash_event
 {
-   my ( $event ) = @_;
+   my ( $event, $room_version ) = @_;
+   $room_version //= 1;
    croak "Require an event" unless ref $event eq 'HASH';
-   my $redacted = redacted_event( $event );
+   my $redacted = redacted_event( $event, $room_version );
    delete $redacted->{signatures};
    delete $redacted->{age_ts};
    delete $redacted->{unsigned};
@@ -76,7 +77,7 @@ sub id_for_event
       return $event_id;
    }
 
-   my $event_hash = hash_event( $event );
+   my $event_hash = hash_event( $event, $room_version );
 
    # room v3 uses the unpadded-base64-encoded hash
    if( $room_version eq '3' ) {
diff --git a/lib/SyTest/Federation/Room.pm b/lib/SyTest/Federation/Room.pm
index f13aae5b1..6f6f00fe1 100644
--- a/lib/SyTest/Federation/Room.pm
+++ b/lib/SyTest/Federation/Room.pm
@@ -180,13 +180,18 @@ sub create_initial_events
       $self->room_version eq "1" ? undef : $self->room_version
    );
 
+   my $create_content = {
+      defined( $room_version ) ? ( room_version => $room_version ) : (),
+   };
+   # Default to old 'creator' field if no room version is specified, or room version is
+   # a numeric value <11. Non-numeric (unstable) versions are treated as 11+.
+   $create_content->{creator} = $creator
+      unless defined( $room_version ) && ( $room_version !~ /\A[0-9]+\z/ || $room_version >= 11 );
+
    $self->create_and_insert_event(
       type => "m.room.create",
 
-      content     => {
-         creator => $creator,
-         defined( $room_version ) ? ( room_version => $room_version ) : (),
-      },
+      content     => $create_content,
       sender      => $creator,
       state_key   => "",
    );
diff --git a/tests/30rooms/01state.pl b/tests/30rooms/01state.pl
index 01bfc274a..cc17d1b0c 100644
--- a/tests/30rooms/01state.pl
+++ b/tests/30rooms/01state.pl
@@ -32,9 +32,19 @@
          $event->{sender} eq $user->user_id or
             die "Expected user_id to be ${\$user->user_id}";
 
-         assert_json_keys( my $content = $event->{content}, qw( creator ));
-         $content->{creator} eq $user->user_id or
-            die "Expected creator to be ${\$user->user_id}";
+         my $content = $event->{content};
+         my $room_version = $content->{room_version} // "1";
+         if( $room_version !~ /\A[0-9]+\z/ || $room_version >= 11 ) {
+            # Room version 11+: 'creator' must be absent from content.
+            exists $content->{creator} and
+               die "Expected no 'creator' key in content for room version $room_version";
+         } else {
+            # Older room versions: 'creator' must be present and match sender.
+            exists $content->{creator} or
+               die "Expected 'creator' key in content for room version $room_version";
+            $content->{creator} eq $user->user_id or
+               die "Expected creator to be ${\$user->user_id}";
+         }
 
          return 1;
       });