diff --git a/lib/RTCSession.d.ts b/lib/RTCSession.d.ts
index b4398202f..73a09be4a 100644
--- a/lib/RTCSession.d.ts
+++ b/lib/RTCSession.d.ts
@@ -43,6 +43,7 @@ export interface AnswerOptions extends ExtraHeaders {
   rtcAnswerConstraints?: RTCOfferOptions;
   rtcOfferConstraints?: RTCOfferOptions;
   sessionTimersExpires?: number;
+  allowEvents?: string[];
 }
 
 export interface RejectOptions extends ExtraHeaders {
@@ -136,6 +137,12 @@ export interface OutgoingInfoEvent {
   request: OutgoingRequest;
 }
 
+export interface NotifyEvent {
+  originator: Originator.REMOTE;
+  type: string;
+  request: IncomingRequest;
+}
+
 export interface HoldEvent {
   originator: Originator
 }
@@ -183,6 +190,7 @@ export type DTMFListener = IncomingDTMFListener | OutgoingDTMFListener;
 export type IncomingInfoListener = (event: IncomingInfoEvent) => void;
 export type OutgoingInfoListener = (event: OutgoingInfoEvent) => void;
 export type InfoListener = IncomingInfoListener | OutgoingInfoListener;
+export type NotifyListener = (event: NotifyEvent) => void
 export type HoldListener = (event: HoldEvent) => void;
 export type MuteListener = (event: MediaConstraints) => void;
 export type ReInviteListener = (event: ReInviteEvent) => void;
@@ -202,6 +210,7 @@ export interface RTCSessionEventMap {
   'failed': EndListener;
   'newDTMF': DTMFListener;
   'newInfo': InfoListener;
+  'newNotify': NotifyListener;
   'hold': HoldListener;
   'unhold': HoldListener;
   'muted': MuteListener;
@@ -244,6 +253,8 @@ export class RTCSession extends EventEmitter {
   set data(_data: any);
   get data(): any;
 
+  set allow_events(events: string[]);
+
   get connection(): RTCPeerConnectionDeprecated;
 
   get contact(): string;
diff --git a/lib/RTCSession.js b/lib/RTCSession.js
index df9e50a56..fe9acdf68 100644
--- a/lib/RTCSession.js
+++ b/lib/RTCSession.js
@@ -134,6 +134,9 @@ module.exports = class RTCSession extends EventEmitter
 
     // Custom session empty object for high level use.
     this._data = {};
+
+    // List of allowed NOTIFY events for the Allow-Events header.
+    this._allowEvents = [];
   }
 
   /**
@@ -202,6 +205,11 @@ module.exports = class RTCSession extends EventEmitter
     this._data = _data;
   }
 
+  set allow_events(events)
+  {
+    this._allowEvents = events;
+  }
+
   get status()
   {
     return this._status;
@@ -283,6 +291,7 @@ module.exports = class RTCSession extends EventEmitter
     this._rtcAnswerConstraints = options.rtcAnswerConstraints || null;
 
     this._data = options.data || this._data;
+    this._allowEvents = options.allowEvents || this._allowEvents;
 
     // Check target.
     if (target === undefined)
@@ -374,6 +383,12 @@ module.exports = class RTCSession extends EventEmitter
       extraHeaders.push(`Session-Expires: ${this._sessionTimers.defaultExpires}${this._ua.configuration.session_timers_force_refresher ? ';refresher=uac' : ''}`);
     }
 
+    // If in-dialog NOTIFY events are allowed the Allow-Events header gets set.
+    if (this._allowEvents.length > 0)
+    {
+      extraHeaders.push(`Allow-Events: ${this._allowEvents.join()}`);
+    }
+
     this._request = new SIPMessage.InitialOutgoingInviteRequest(
       target, this._ua, requestParams, extraHeaders);
 
@@ -495,8 +510,16 @@ module.exports = class RTCSession extends EventEmitter
       return;
     }
 
+    const extraHeaders = [ `Contact: ${this._contact}` ];
+
+    // If in-dialog NOTIFY events are allowed the Allow-Events header gets set.
+    if (this._allowEvents.length > 0)
+    {
+      extraHeaders.push(`Allow-Events: ${this._allowEvents.join()}`);
+    }
+
     // Reply 180.
-    request.reply(180, null, [ `Contact: ${this._contact}` ]);
+    request.reply(180, null, extraHeaders);
 
     // Fire 'progress' event.
     // TODO: Document that 'response' field in 'progress' event is null for incoming calls.
@@ -529,6 +552,7 @@ module.exports = class RTCSession extends EventEmitter
     this._rtcOfferConstraints = options.rtcOfferConstraints || null;
 
     this._data = options.data || this._data;
+    this._allowEvents = options.allowEvents || this._allowEvents;
 
     // Check Session Direction and Status.
     if (this._direction !== 'incoming')
@@ -572,6 +596,12 @@ module.exports = class RTCSession extends EventEmitter
 
     extraHeaders.unshift(`Contact: ${this._contact}`);
 
+    // If in-dialog NOTIFY events are allowed the Allow-Events header gets set.
+    if (this._allowEvents.length > 0)
+    {
+      extraHeaders.push(`Allow-Events: ${this._allowEvents.join()}`);
+    }
+
     // Determine incoming media from incoming SDP offer (if any).
     const sdp = request.parseSDP();
 
@@ -1598,7 +1628,11 @@ module.exports = class RTCSession extends EventEmitter
           }
           break;
         case JsSIP_C.NOTIFY:
-          if (this._status === C.STATUS_CONFIRMED)
+          if (this._status === C.STATUS_1XX_RECEIVED ||
+            this._status === C.STATUS_WAITING_FOR_ANSWER ||
+            this._status === C.STATUS_ANSWERED ||
+            this._status === C.STATUS_WAITING_FOR_ACK ||
+            this._status === C.STATUS_CONFIRMED)
           {
             this._receiveNotify(request);
           }
@@ -2505,9 +2539,10 @@ module.exports = class RTCSession extends EventEmitter
       request.reply(400);
     }
 
-    switch (request.event.event)
+    if (request.event.event === 'refer')
     {
-      case 'refer': {
+      if (this._status === C.STATUS_CONFIRMED)
+      {
         let id;
         let referSubscriber;
 
@@ -2537,14 +2572,26 @@ module.exports = class RTCSession extends EventEmitter
 
         referSubscriber.receiveNotify(request);
         request.reply(200);
-
-        break;
       }
-
-      default: {
-        request.reply(489);
+      else
+      {
+        request.reply(403, 'Wrong Status');
       }
     }
+    else if (this._allowEvents.indexOf(request.event.event) !== -1)
+    {
+      this.emit('newNotify', {
+        originator : 'remote',
+        type       : request.event.event,
+        request    : request
+      });
+
+      request.reply(200);
+    }
+    else
+    {
+      request.reply(489);
+    }
   }
 
   /**