diff --git a/tests/csapi/device_lists_test.go b/tests/csapi/device_lists_test.go
index 7012efa7..64f356a2 100644
--- a/tests/csapi/device_lists_test.go
+++ b/tests/csapi/device_lists_test.go
@@ -125,7 +125,18 @@ func TestDeviceListUpdates(t *testing.T) {
 		})
 
 		// The observing user must share a room with the dummy barrier user.
-		roomID := barry.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+		roomID := barry.MustCreateRoom(t, map[string]interface{}{
+			"preset": "public_chat",
+			"initial_state": []map[string]interface{}{
+				{
+					"type":      "m.room.encryption",
+					"state_key": "",
+					"content": map[string]interface{}{
+						"algorithm": "m.megolm.v1.aes-sha2",
+					},
+				},
+			},
+		})
 		observingUser.MustJoinRoom(t, roomID, []spec.ServerName{
 			deployment.GetFullyQualifiedHomeserverName(t, otherHSName),
 		})
@@ -160,7 +171,18 @@ func TestDeviceListUpdates(t *testing.T) {
 		barrier := makeBarrier(t, deployment, alice, otherHSName)
 		checkBobKeys := uploadNewKeys(t, bob)
 
-		roomID := alice.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+		roomID := alice.MustCreateRoom(t, map[string]interface{}{
+			"preset": "public_chat",
+			"initial_state": []map[string]interface{}{
+				{
+					"type":      "m.room.encryption",
+					"state_key": "",
+					"content": map[string]interface{}{
+						"algorithm": "m.megolm.v1.aes-sha2",
+					},
+				},
+			},
+		})
 		t.Logf("%s created test room %s.", alice.UserID, roomID)
 
 		// Alice performs an initial sync
@@ -215,7 +237,18 @@ func TestDeviceListUpdates(t *testing.T) {
 		barrier := makeBarrier(t, deployment, alice, otherHSName)
 		checkBobKeys := uploadNewKeys(t, bob)
 
-		roomID := bob.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+		roomID := bob.MustCreateRoom(t, map[string]interface{}{
+			"preset": "public_chat",
+			"initial_state": []map[string]interface{}{
+				{
+					"type":      "m.room.encryption",
+					"state_key": "",
+					"content": map[string]interface{}{
+						"algorithm": "m.megolm.v1.aes-sha2",
+					},
+				},
+			},
+		})
 		t.Logf("%s created test room %s.", bob.UserID, roomID)
 
 		// Alice performs an initial sync
@@ -268,7 +301,18 @@ func TestDeviceListUpdates(t *testing.T) {
 		barrier := makeBarrier(t, deployment, alice, otherHSName)
 		checkBobKeys := uploadNewKeys(t, bob)
 
-		roomID := alice.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+		roomID := alice.MustCreateRoom(t, map[string]interface{}{
+			"preset": "public_chat",
+			"initial_state": []map[string]interface{}{
+				{
+					"type":      "m.room.encryption",
+					"state_key": "",
+					"content": map[string]interface{}{
+						"algorithm": "m.megolm.v1.aes-sha2",
+					},
+				},
+			},
+		})
 		t.Logf("%s created test room %s.", alice.UserID, roomID)
 
 		// Bob joins the room
@@ -327,7 +371,18 @@ func TestDeviceListUpdates(t *testing.T) {
 		barrier := makeBarrier(t, deployment, alice, otherHSName)
 		checkBobKeys := uploadNewKeys(t, bob)
 
-		roomID := bob.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+		roomID := bob.MustCreateRoom(t, map[string]interface{}{
+			"preset": "public_chat",
+			"initial_state": []map[string]interface{}{
+				{
+					"type":      "m.room.encryption",
+					"state_key": "",
+					"content": map[string]interface{}{
+						"algorithm": "m.megolm.v1.aes-sha2",
+					},
+				},
+			},
+		})
 		t.Logf("%s created test room %s.", bob.UserID, roomID)
 
 		// Alice joins the room
@@ -386,7 +441,18 @@ func TestDeviceListUpdates(t *testing.T) {
 		barrier := makeBarrier(t, deployment, alice, otherHSName)
 		checkBobKeys := uploadNewKeys(t, bob)
 
-		roomID := alice.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+		roomID := alice.MustCreateRoom(t, map[string]interface{}{
+			"preset": "public_chat",
+			"initial_state": []map[string]interface{}{
+				{
+					"type":      "m.room.encryption",
+					"state_key": "",
+					"content": map[string]interface{}{
+						"algorithm": "m.megolm.v1.aes-sha2",
+					},
+				},
+			},
+		})
 		t.Logf("%s created test room %s.", alice.UserID, roomID)
 
 		// Bob joins the room
diff --git a/tests/csapi/keychanges_test.go b/tests/csapi/keychanges_test.go
index 63437bdc..84787cc7 100644
--- a/tests/csapi/keychanges_test.go
+++ b/tests/csapi/keychanges_test.go
@@ -32,7 +32,18 @@ func TestKeyChangesLocal(t *testing.T) {
 		bobDeviceKeys, bobOTKs := bob.MustGenerateOneTimeKeys(t, 1)
 		bob.MustUploadKeys(t, bobDeviceKeys, bobOTKs)
 
-		roomID := alice.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+		roomID := alice.MustCreateRoom(t, map[string]interface{}{
+			"preset": "public_chat",
+			"initial_state": []map[string]interface{}{
+				{
+					"type":      "m.room.encryption",
+					"state_key": "",
+					"content": map[string]interface{}{
+						"algorithm": "m.megolm.v1.aes-sha2",
+					},
+				},
+			},
+		})
 		bob.MustJoinRoom(t, roomID, []spec.ServerName{})
 		nextBatch1 := alice.MustSyncUntil(t, client.SyncReq{}, client.SyncJoinedTo(bob.UserID, roomID))
 
@@ -45,7 +56,7 @@ func TestKeyChangesLocal(t *testing.T) {
 			"password": password,
 		})
 		// Create a new device by logging in
-		res := unauthedClient.MustDo(t, "POST", []string{"_matrix", "client", "r0", "login"}, reqBody)
+		res := unauthedClient.MustDo(t, "POST", []string{"_matrix", "client", "v3", "login"}, reqBody)
 		loginResp := must.ParseJSON(t, res.Body)
 		unauthedClient.AccessToken = must.GetJSONFieldStr(t, loginResp, "access_token")
 		unauthedClient.DeviceID = must.GetJSONFieldStr(t, loginResp, "device_id")
diff --git a/tests/csapi/sync_test.go b/tests/csapi/sync_test.go
index 3dec9ea5..13b13764 100644
--- a/tests/csapi/sync_test.go
+++ b/tests/csapi/sync_test.go
@@ -405,7 +405,18 @@ func TestSync(t *testing.T) {
 				// Regression test for https://github.com/element-hq/synapse/issues/16948
 
 				charlie := deployment.Register(t, "hs1", helpers.RegistrationOpts{LocalpartSuffix: "charlie"})
-				roomID := alice.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+				roomID := alice.MustCreateRoom(t, map[string]interface{}{
+					"preset": "public_chat",
+					"initial_state": []map[string]interface{}{
+						{
+							"type":      "m.room.encryption",
+							"state_key": "",
+							"content": map[string]interface{}{
+								"algorithm": "m.megolm.v1.aes-sha2",
+							},
+						},
+					},
+				})
 
 				aliceSyncFilter := `{
 				    "room": {
diff --git a/tests/federation_device_list_update_test.go b/tests/federation_device_list_update_test.go
index 770535c8..87c7c4b5 100644
--- a/tests/federation_device_list_update_test.go
+++ b/tests/federation_device_list_update_test.go
@@ -206,7 +206,14 @@ func TestDeviceListsUpdateOverFederationOnRoomJoin(t *testing.T) {
 	bob := srv.UserID("complement_bob")
 	roomVer := gomatrixserverlib.RoomVersion("10")
 	initalEvents := federation.InitialRoomEvents(roomVer, bob)
-	room := srv.MustMakeRoom(t, roomVer, initalEvents)
+	room := srv.MustMakeRoom(t, roomVer, append(initalEvents, federation.Event{
+		Type:     "m.room.encryption",
+		StateKey: b.Ptr(""),
+		Sender:   bob,
+		Content: map[string]interface{}{
+			"algorithm": "m.megolm.v1.aes-sha2",
+		},
+	}))
 
 	alice.MustJoinRoom(t, room.RoomID, []spec.ServerName{srv.ServerName()})
 	alice.SendEventSynced(t, room.RoomID, b.Event{
diff --git a/tests/federation_upload_keys_test.go b/tests/federation_upload_keys_test.go
index 2f91485e..8af57548 100644
--- a/tests/federation_upload_keys_test.go
+++ b/tests/federation_upload_keys_test.go
@@ -24,7 +24,18 @@ func TestFederationKeyUploadQuery(t *testing.T) {
 	bob := deployment.Register(t, "hs2", helpers.RegistrationOpts{})
 
 	// for device lists to be shared between alice and bob they must share a room
-	roomID := alice.MustCreateRoom(t, map[string]interface{}{"preset": "public_chat"})
+	roomID := alice.MustCreateRoom(t, map[string]interface{}{
+		"preset": "public_chat",
+		"initial_state": []map[string]interface{}{
+			{
+				"type":      "m.room.encryption",
+				"state_key": "",
+				"content": map[string]interface{}{
+					"algorithm": "m.megolm.v1.aes-sha2",
+				},
+			},
+		},
+	})
 	bob.MustJoinRoom(t, roomID, []spec.ServerName{
 		deployment.GetFullyQualifiedHomeserverName(t, "hs1"),
 	})