diff --git a/src/client.ts b/src/client.ts
index e9cf8fff1..975de9f01 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -40,7 +40,6 @@ import { sleep } from './utils';
 import { Direction, EventTimeline } from "./models/event-timeline";
 import { IActionsObject, PushProcessor } from "./pushprocessor";
 import { AutoDiscovery, AutoDiscoveryAction } from "./autodiscovery";
-import { IEncryptAndSendToDevicesResult } from "./crypto";
 import * as olmlib from "./crypto/olmlib";
 import { decodeBase64, encodeBase64 } from "./crypto/olmlib";
 import { IExportedDevice as IExportedOlmDevice } from "./crypto/OlmDevice";
@@ -2583,7 +2582,7 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
     public encryptAndSendToDevices(
         userDeviceInfoArr: IOlmDevice<DeviceInfo>[],
         payload: object,
-    ): Promise<IEncryptAndSendToDevicesResult> {
+    ): Promise<void> {
         if (!this.crypto) {
             throw new Error("End-to-End encryption disabled");
         }
diff --git a/src/crypto/algorithms/megolm.ts b/src/crypto/algorithms/megolm.ts
index 50fed9ebb..e82008fd8 100644
--- a/src/crypto/algorithms/megolm.ts
+++ b/src/crypto/algorithms/megolm.ts
@@ -606,19 +606,19 @@ class MegolmEncryption extends EncryptionAlgorithm {
     private encryptAndSendKeysToDevices(
         session: OutboundSessionInfo,
         chainIndex: number,
-        userDeviceMap: IOlmDevice[],
+        devices: IOlmDevice[],
         payload: IPayload,
     ): Promise<void> {
         return this.crypto.encryptAndSendToDevices(
-            userDeviceMap,
+            devices,
             payload,
-        ).then(({ toDeviceBatch, deviceInfoByUserIdAndDeviceId }) => {
+        ).then(() => {
             // store that we successfully uploaded the keys of the current slice
-            for (const msg of toDeviceBatch.batch) {
+            for (const device of devices) {
                 session.markSharedWithDevice(
-                    msg.userId,
-                    msg.deviceId,
-                    deviceInfoByUserIdAndDeviceId.get(msg.userId).get(msg.deviceId).getIdentityKey(),
+                    device.userId,
+                    device.deviceInfo.deviceId,
+                    device.deviceInfo.getIdentityKey(),
                     chainIndex,
                 );
             }
diff --git a/src/crypto/index.ts b/src/crypto/index.ts
index ff5ab43fe..451d2d8c8 100644
--- a/src/crypto/index.ts
+++ b/src/crypto/index.ts
@@ -212,11 +212,6 @@ export interface IEncryptedContent {
 }
 /* eslint-enable camelcase */
 
-export interface IEncryptAndSendToDevicesResult {
-    toDeviceBatch: ToDeviceBatch;
-    deviceInfoByUserIdAndDeviceId: Map<string, Map<string, DeviceInfo>>;
-}
-
 export enum CryptoEvent {
     DeviceVerificationChanged = "deviceVerificationChanged",
     UserTrustStatusChanged = "userTrustStatusChanged",
@@ -3129,12 +3124,11 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
     public async encryptAndSendToDevices(
         userDeviceInfoArr: IOlmDevice<DeviceInfo>[],
         payload: object,
-    ): Promise<IEncryptAndSendToDevicesResult> {
+    ): Promise<void> {
         const toDeviceBatch: ToDeviceBatch = {
             eventType: EventType.RoomMessageEncrypted,
             batch: [],
         };
-        const deviceInfoByUserIdAndDeviceId = new Map<string, Map<string, DeviceInfo>>();
 
         try {
             await Promise.all(userDeviceInfoArr.map(async ({ userId, deviceInfo }) => {
@@ -3145,17 +3139,6 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
                     ciphertext: {},
                 };
 
-                // Assign to temp value to make type-checking happy
-                let userIdDeviceInfo = deviceInfoByUserIdAndDeviceId.get(userId);
-
-                if (userIdDeviceInfo === undefined) {
-                    userIdDeviceInfo = new Map<string, DeviceInfo>();
-                    deviceInfoByUserIdAndDeviceId.set(userId, userIdDeviceInfo);
-                }
-
-                // We hold by reference, this updates deviceInfoByUserIdAndDeviceId[userId]
-                userIdDeviceInfo.set(deviceId, deviceInfo);
-
                 toDeviceBatch.batch.push({
                     userId,
                     deviceId,
@@ -3193,7 +3176,6 @@ export class Crypto extends TypedEventEmitter<CryptoEvent, CryptoEventHandlerMap
 
             try {
                 await this.baseApis.queueToDevice(toDeviceBatch);
-                return { toDeviceBatch, deviceInfoByUserIdAndDeviceId };
             } catch (e) {
                 logger.error("sendToDevice failed", e);
                 throw e;