diff --git a/src/Call.d.ts b/src/Call.d.ts
index 957ff29..3f46bb2 100644
--- a/src/Call.d.ts
+++ b/src/Call.d.ts
@@ -387,9 +387,21 @@ declare global {
          * the first playing. Supported formats are: mp3, ogg & flac (mp3,
          * speex, vorbis and flac codecs respectively). Maximum file size is
          * 2 MBytes.
-         * @param loop If it's true, playback will be looped.
+         * @param options Playback parameters: loop, progressive playback,
+         * etc.
          */
-        startPlayback(url: string, loop: boolean): void;
+        startPlayback(url: string, options: {
+            /**
+             * If it's true, playback will be looped.
+             */
+            loop: boolean; 
+            /**
+             * Use progressive playback or not. If true, the file will be 
+             * delivered in chunks which reduces delay before a method call 
+             * and playback. It's false by default.
+            */
+            progressivePlayback: boolean;
+        }): void;
 
         /**
          * Returns current state of the call. Possible values are:
diff --git a/src/Modules/ACD/ACDEvents.d.ts b/src/Modules/ACD/ACDEvents.d.ts
index e33b5be..2e49207 100644
--- a/src/Modules/ACD/ACDEvents.d.ts
+++ b/src/Modules/ACD/ACDEvents.d.ts
@@ -2,6 +2,7 @@ import './ACDEvents/Error';
 import './ACDEvents/Offline';
 import './ACDEvents/OperatorFailed';
 import './ACDEvents/OperatorReached';
+import './ACDEvents/OperatorCallAttempt';
 import './ACDEvents/Queued';
 import './ACDEvents/QueueFull';
 import './ACDEvents/Waiting';
@@ -15,6 +16,7 @@ declare global {
         export type Offline = () => Offline.Event;
         export type OperatorFailed = () => OperatorFailed.Event;
         export type OperatorReached = () => OperatorReached.Event;
+        export type OperatorCallAttempt = () => OperatorCallAttempt.Event;
         export type Queued = () => Queued.Event;
         export type QueueFull = () => QueueFull.Event;
         export type Waiting = () => Waiting.Event;
@@ -23,6 +25,7 @@ declare global {
         export const Offline: Offline;
         export const OperatorFailed: OperatorFailed;
         export const OperatorReached: OperatorReached;
+        export const OperatorCallAttempt: OperatorCallAttempt;
         export const Queued: Queued;
         export const QueueFull: QueueFull;
         export const Waiting: Waiting;
@@ -33,6 +36,7 @@ declare global {
         ACDEvents.Offline |
         ACDEvents.OperatorFailed |
         ACDEvents.OperatorReached |
+        ACDEvents.OperatorCallAttempt |
         ACDEvents.Queued |
         ACDEvents.QueueFull |
         ACDEvents.Waiting;
diff --git a/src/Modules/ACD/ACDEvents/OperatorCallAttempt.d.ts b/src/Modules/ACD/ACDEvents/OperatorCallAttempt.d.ts
new file mode 100644
index 0000000..ce8241e
--- /dev/null
+++ b/src/Modules/ACD/ACDEvents/OperatorCallAttempt.d.ts
@@ -0,0 +1,25 @@
+import '../../../Call';
+import {ACDRequestEvent} from './$Implicit/ACDRequestEvent';
+import {EventHandler} from '../../../$Implicit/EventHandler';
+
+export = ACDEvents;
+
+declare global {
+    export namespace ACDEvents {
+        export namespace OperatorCallAttempt {
+            /**
+             * The event is triggered when an ACD makes a user call 
+             * via the {@link https://voximplant.com/docs/references/voxengine/voxengine/calluser|CallUser}
+             * method.
+             */
+            export interface Event extends ACDRequestEvent {
+                /**
+                 * Operator's call
+                 */
+                readonly operatorCall: Call;
+            }
+
+            export interface Handler extends EventHandler<Event> {}
+        }
+    }
+}