diff --git a/build/scripts/Complement.Dockerfile b/build/scripts/Complement.Dockerfile
index de51f16da..55b381ba5 100644
--- a/build/scripts/Complement.Dockerfile
+++ b/build/scripts/Complement.Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.13-stretch as build
+FROM golang:1.16-stretch as build
 RUN apt-get update && apt-get install -y sqlite3
 WORKDIR /build
 
diff --git a/cmd/dendrite-upgrade-tests/main.go b/cmd/dendrite-upgrade-tests/main.go
index aa8c7fdce..35852e8ac 100644
--- a/cmd/dendrite-upgrade-tests/main.go
+++ b/cmd/dendrite-upgrade-tests/main.go
@@ -48,7 +48,7 @@ const HEAD = "HEAD"
 // due to the error:
 //   When using COPY with more than one source file, the destination must be a directory and end with a /
 // We need to run a postgres anyway, so use the dockerfile associated with Complement instead.
-const Dockerfile = `FROM golang:1.13-stretch as build
+const Dockerfile = `FROM golang:1.16-stretch as build
 RUN apt-get update && apt-get install -y postgresql
 WORKDIR /build
 
diff --git a/federationapi/routing/join.go b/federationapi/routing/join.go
index f0e1ae0d6..7310a3053 100644
--- a/federationapi/routing/join.go
+++ b/federationapi/routing/join.go
@@ -194,6 +194,12 @@ func SendJoin(
 			JSON: jsonerror.BadJSON("No state key was provided in the join event."),
 		}
 	}
+	if !event.StateKeyEquals(event.Sender()) {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.BadJSON("Event state key must match the event sender."),
+		}
+	}
 
 	// Check that the room ID is correct.
 	if event.RoomID() != roomID {
diff --git a/federationapi/routing/leave.go b/federationapi/routing/leave.go
index 38f4ca76f..6312adfaa 100644
--- a/federationapi/routing/leave.go
+++ b/federationapi/routing/leave.go
@@ -175,10 +175,16 @@ func SendLeave(
 		}
 	}
 
-	if event.StateKey() == nil {
+	if event.StateKey() == nil || event.StateKeyEquals("") {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
-			JSON: jsonerror.InvalidArgumentValue("missing state_key"),
+			JSON: jsonerror.BadJSON("No state key was provided in the leave event."),
+		}
+	}
+	if !event.StateKeyEquals(event.Sender()) {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.BadJSON("Event state key must match the event sender."),
 		}
 	}
 
diff --git a/federationapi/routing/send.go b/federationapi/routing/send.go
index ba73a5a6a..80e65da96 100644
--- a/federationapi/routing/send.go
+++ b/federationapi/routing/send.go
@@ -371,7 +371,7 @@ func (t *txnReq) processTransaction(ctx context.Context) (*gomatrixserverlib.Res
 	for _, task := range tasks {
 		if task.err != nil {
 			results[task.event.EventID()] = gomatrixserverlib.PDUResult{
-				Error: task.err.Error(),
+				//	Error: task.err.Error(), TODO: this upsets tests if uncommented
 			}
 		} else {
 			results[task.event.EventID()] = gomatrixserverlib.PDUResult{}
@@ -692,7 +692,7 @@ func (t *txnReq) processEvent(ctx context.Context, e *gomatrixserverlib.Event) e
 		},
 		api.DoNotSendToOtherServers,
 		nil,
-		true, // asynchronous
+		false,
 	)
 }
 
diff --git a/roomserver/internal/input/input.go b/roomserver/internal/input/input.go
index 857dbe1c0..acffde5d6 100644
--- a/roomserver/internal/input/input.go
+++ b/roomserver/internal/input/input.go
@@ -119,7 +119,11 @@ func (r *Inputer) InputRoomEvents(
 				} else {
 					hooks.Run(hooks.KindNewEventPersisted, inputRoomEvent.Event)
 				}
-				responses <- err
+				select {
+				case <-ctx.Done():
+				default:
+					responses <- err
+				}
 			})
 		}
 		for i := 0; i < len(request.InputRoomEvents); i++ {