diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ef6033..bf298a9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,17 @@
 # Change Log
 
-## [v4.21.0](https://github.com/plivo/plivo-node/tree/v4.21.0) (2021-07-20)
-- This version includes advancements to the Messaging Interface that deals with the [Send SMS/MMS](https://www.plivo.com/docs/sms/api/message#send-a-message) interface, Creating a standard structure for `request/input` arguments to make implementation easier and incorporating support for the older interface.
+## [v4.22.0](https://github.com/plivo/plivo-node/tree/v4.22.0) (2021-08-17)
+- Fix [add numbers to a powerpack](https://www.plivo.com/docs/sms/api/numberpool/#add-a-number) API by reverting retrievable object responses support for [Retrieve a Power pack API](https://www.plivo.com/docs/sms/api/powerpack#retrieve-a-powerpack).
+
+## [v4.21.0](https://github.com/plivo/plivo-node/tree/v4.21.0) (2021-08-05)
+- Fixed a Typescript warning about base interpretation.
+- Add retrievable object responses support for [Retrieve a Power pack API](https://www.plivo.com/docs/sms/api/powerpack#retrieve-a-powerpack).
+
+## [v4.20.1](https://github.com/plivo/plivo-node/tree/v4.20.1) (2021-07-27)
+- Updates to [add a member a multi-party call API](https://www.plivo.com/docs/voice/api/multiparty-call/participants#add-a-participant).
+  - Remove validation range for `delay` and `ringtimeout` parameters.
+  - Add appropriate error message for multiple `ringtimeout` and `delaydial` values.
+- Updated default HTTP client request timeout to 5 seconds.
 
 ## [v4.20.0](https://github.com/plivo/plivo-node/tree/v4.20.0) (2021-07-13)
 - Power pack ID has been included to the response for the [list all messages API](https://www.plivo.com/docs/sms/api/message/list-all-messages/) and the [get message details API](https://www.plivo.com/docs/sms/api/message#retrieve-a-message).
diff --git a/lib/resources/multiPartyCall.js b/lib/resources/multiPartyCall.js
index 0fe35c6..3fee3f8 100644
--- a/lib/resources/multiPartyCall.js
+++ b/lib/resources/multiPartyCall.js
@@ -106,24 +106,24 @@ export class MultiPartyCall extends PlivoResource{
 
     if(params.ringTimeout || params.ringTimeout === 0){
       validParam('ringTimeout', params.ringTimeout, [String, Number], false)
-      if(Number.isInteger(params.ringTimeout)){
-        validRange('RingTimeout', params.ringTimeout, false, 15, 120)
-      }
-      else{
+      if(typeof(params.ringTimeout) === 'string'){
         validMultipleDestinationIntegers('ringTimeout', params.ringTimeout)
       }
+      else if (!Number.isInteger(params.ringTimeout) && typeof(params.ringTimeout) !== 'string'){
+        throw new InvalidRequestError("RingTimeout must be of type int or string")
+      }
     }
     else {
       params.ringTimeout = 45
     }
     if(params.delayDial){
       validParam('delayDial', params.delayDial, [String, Number], false)
-      if(Number.isInteger(params.delayDial)){
-        validRange('DelayDial', params.delayDial, false, 1, 120)
-      }
-      else{
+      if(typeof(params.delayDial) === 'string'){
         validMultipleDestinationIntegers('delayDial', params.delayDial)
       }
+      else if(!Number.isInteger(params.delayDial) && typeof(params.delayDial) !== 'string'){
+        throw new InvalidRequestError("Dealydial must be of type int or string")
+      }
     }
     else {
       params.delayDial = 0
@@ -306,6 +306,12 @@ export class MultiPartyCall extends PlivoResource{
     else {
       params.exitSoundMethod = 'GET'
     }
+    if(params.to && (String(params.ringTimeout).split('<').length > params.to.split('<').length)){
+      throw new MPCError("RingTimeout:number of ring_timeout(s) should be same as number of destination(s)")
+    }
+    if(params.to && (String(params.delayDial).split('<').length > params.to.split('<').length)){
+      throw new MPCError("DelayDial:number of delay_dial(s) should be same as number of destination(s)")
+    }
     params.isVoiceRequest = 'true';
     params.callerName = params.callerName || params.from;
     return super.executeAction(this.id + '/Participant/', 'POST', params)
diff --git a/lib/resources/numbers.js b/lib/resources/numbers.js
index ccaec8b..b275123 100644
--- a/lib/resources/numbers.js
+++ b/lib/resources/numbers.js
@@ -1,4 +1,5 @@
 import {
+    PlivoGenericResponse,
     PlivoResource,
     PlivoResourceInterface
 } from '../base';
@@ -271,7 +272,15 @@ export class NumberInterface extends PlivoResourceInterface {
         params.carrier = carrier;
         params.region = region;
 
-        return super.create(params);
+        return new Promise((resolve, reject) => {
+            client('POST', action, params)
+                .then(response => {
+                    resolve(new PlivoGenericResponse(response.body, idField));
+                })
+                .catch(error => {
+                    reject(error);
+                });
+        })
     }
 
     /**
diff --git a/lib/resources/powerpacks.js b/lib/resources/powerpacks.js
index 9e96fed..2df1d4c 100644
--- a/lib/resources/powerpacks.js
+++ b/lib/resources/powerpacks.js
@@ -457,7 +457,6 @@ export class Powerpack extends PlivoResource {
    * @param {string} [params.sticky_sender]
    * @param {string} [params.local_connect]
    * @param {object} [params.number_priority]
-
    * @promise {object} return {@link Powerpack} object
    * @fail {Error} return Error
    */
@@ -696,7 +695,7 @@ export class PowerpackInterface extends PlivoResourceInterface {
      * @promise {object} return {@link Powerpack} object
      * @fail {Error} return Error
      */
-    get(uuid) {
+     get(uuid) {
         return super.get(uuid);
     }
     /**
@@ -777,4 +776,4 @@ export class PowerpackInterface extends PlivoResourceInterface {
     list(params) {
         return super.list(params);
     }
-}
\ No newline at end of file
+}
diff --git a/lib/rest/axios.js b/lib/rest/axios.js
index 5316274..ba74448 100644
--- a/lib/rest/axios.js
+++ b/lib/rest/axios.js
@@ -175,6 +175,9 @@ export function Axios(config) {
     if (typeof config.timeout !== 'undefined') {
       options.timeout = config.timeout;
     }
+    else if(typeof config.timeout === 'undefined'){
+      options.timeout = 5000;
+    }
 
     return new Promise((resolve, reject) => {
       if (isVoiceReq) {
diff --git a/lib/rest/request-test.js b/lib/rest/request-test.js
index 18e1791..012a817 100644
--- a/lib/rest/request-test.js
+++ b/lib/rest/request-test.js
@@ -1,5 +1,5 @@
-import request from 'request';
 import queryString from 'querystring';
+import request from 'request';
 
 export function Request(config) {
   let auth = 'Basic ' + new Buffer(config.authId + ':' + config.authToken)
@@ -1465,4 +1465,4 @@ export function Request(config) {
       }
     });
   };
-}
+}
\ No newline at end of file
diff --git a/lib/rest/request.js b/lib/rest/request.js
index 94f1c72..67fd730 100644
--- a/lib/rest/request.js
+++ b/lib/rest/request.js
@@ -1,8 +1,9 @@
-import request from 'request';
-import queryString from 'querystring';
 import * as Exceptions from '../utils/exceptions';
 import * as _ from "lodash";
 
+import queryString from 'querystring';
+import request from 'request';
+
 export function Request(config) {
   let auth = 'Basic ' + new Buffer(config.authId + ':' + config.authToken)
     .toString('base64');
@@ -219,4 +220,4 @@ export function Request(config) {
       });
     });
   };
-}
+}
\ No newline at end of file
diff --git a/lib/rest/utils.js b/lib/rest/utils.js
index 8a7538c..934836c 100644
--- a/lib/rest/utils.js
+++ b/lib/rest/utils.js
@@ -115,17 +115,7 @@ export function validMultipleDestinationNos(paramName, paramValue, options = {})
 export function validMultipleDestinationIntegers(paramName, paramValue){
   let val = paramValue.split("<");
   for (let i=0; i<val.length; i++){
-    if (!isNaN(val[i]) && Number.isInteger(parseFloat(val[i]))){
-      if(paramName=="delayDial"){
-        if(val[i]!='0'){
-          validRange('DelayDial Destination Value', parseInt(val[i]), false, 1, 120);
-        }
-      }
-      else if (paramName=="ringTimeout"){
-        validRange('RingTimeout Destination Value', parseInt(val[i]), false, 15, 120);
-      }
-    }
-    else{
+    if (!(/^-?\d+$/.test(val[i]))){
       throw new InvalidRequestError( paramName + " Destination value must be integer");
     }
   }
diff --git a/package-lock.json b/package-lock.json
index 347cb92..d516358 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -5591,4 +5591,4 @@
       "dev": true
     }
   }
-}
+}
\ No newline at end of file
diff --git a/package.json b/package.json
index a471bda..e76ea7e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "plivo",
-  "version": "4.21.0",
+  "version": "4.22.0",
   "description": "A Node.js SDK to make voice calls and send SMS using Plivo and to generate Plivo XML",
   "homepage": "https://github.com/plivo/plivo-node",
   "files": [
diff --git a/types/base.d.ts b/types/base.d.ts
index b53c07b..337f69a 100644
--- a/types/base.d.ts
+++ b/types/base.d.ts
@@ -4,8 +4,8 @@ export class PlivoGenericResponse {
 }
 export class PlivoResource {
     constructor(action: string, Klass: Symbol, idField: string, request: any);
-    update(params: object, id: string): Promise<any>;
-    delete(params: object): Promise<any>;
+    // update(params: any, id: any): Promise<any>;
+    delete(params: any): Promise<any>;
     executeAction(task: string, method: string, params: {}, action: string): Promise<any>;
     customexecuteAction(url: string, method?: string, params?: {}): Promise<any>;
     customexecuteGetNumberAction(url: string, method?: string, params?: {}): any;
@@ -13,7 +13,7 @@ export class PlivoResource {
 }
 export class PlivoResourceInterface {
     constructor(action: string, Klass: Symbol, idField: string, request: any);
-    get(id: string, params?: {}): Promise<any>;
-    list(params: object): Promise<any>;
-    create(params: object): Promise<any>;
-}
+    // get(id: any, params?: {}): Promise<any>;
+    // create(params: any): Promise<any>;
+    list(params: any): Promise<any>;
+}
\ No newline at end of file
diff --git a/types/resources/endUsers.d.ts b/types/resources/endUsers.d.ts
index fbdca55..f3efc54 100644
--- a/types/resources/endUsers.d.ts
+++ b/types/resources/endUsers.d.ts
@@ -29,7 +29,7 @@ export class ListEndUsersResponse {
     constructor(params: object);
     apiId: string;
     meta: Object;
-    objects: Array;
+    objects: Array<string>;
 }
 
 /**
diff --git a/types/resources/media.d.ts b/types/resources/media.d.ts
index fe251e5..ca38f5f 100644
--- a/types/resources/media.d.ts
+++ b/types/resources/media.d.ts
@@ -42,7 +42,7 @@ export class MediaInterface extends PlivoResourceInterface {
 	 * @method
 	 * @fail {Error} return Error
 	 */
-    upload(files: Array): Promise<UploadMediaResponse>;
+    upload(files: Array<string>): Promise<UploadMediaResponse>;
     /**
      * Get Media by given id
      * @method
diff --git a/types/resources/messages.d.ts b/types/resources/messages.d.ts
index c709edc..a72264f 100644
--- a/types/resources/messages.d.ts
+++ b/types/resources/messages.d.ts
@@ -23,7 +23,7 @@ export class MessageGetResponse {
 }
 export class MessageListResponse {
 	constructor(params: object);
-    errorCode: string;
+  errorCode: string;
 	fromNumber: string;
 	messageDirection: string;
 	messageState: string;
@@ -34,7 +34,7 @@ export class MessageListResponse {
 	toNumber: string;
 	totalAmount: string;
 	totalRate: string;
-    units: string;
+  units: string;
 	powerpackId: string;
 }
 export class MMSMediaResponse {
@@ -90,7 +90,7 @@ export class MessageInterface extends PlivoResourceInterface {
 		type: string;
 		url: string;
 		method: string;
-		media_urls: Array;
+		media_urls: Array<string>;
 		log: boolean;
 	}): Promise < MessageResponse > ;
 	/**
diff --git a/types/resources/powerpacks.d.ts b/types/resources/powerpacks.d.ts
index 1892aa3..a6d3492 100644
--- a/types/resources/powerpacks.d.ts
+++ b/types/resources/powerpacks.d.ts
@@ -17,6 +17,21 @@ export class CreatePowerpackResponse {
 	stickySender: string;
 	uuid: string;
 }
+
+export class RetrievePowerpack {
+	constructor(params: object);
+	apiId: string;
+	applicationId: string;
+	applicationType: string;
+	createdOn: string;
+	localConnect: string;
+	name: string;
+	numberPool: string;
+	numberPriority: object;
+	stickySender: string;
+	uuid: string;
+}
+
 export class UpdatePowerpackResponse {
 	constructor(params: object);
 	apiId: string;
@@ -179,7 +194,7 @@ export class PowerpackInterface extends PlivoResourceInterface {
      * @promise {object} return {@link Powerpack} object
      * @fail {Error} return Error
      */
-    get(uuid: string): any;
+    get(uuid: string): Promise<RetrievePowerpack>;
     /**
      * create Powerpack
      * @method
@@ -189,7 +204,7 @@ export class PowerpackInterface extends PlivoResourceInterface {
      * @param {string} [params.local_connect]
      * @param {string} [params.application_type]
      * @param {string} [params.application_id]
-     * @promise {object} return {@link PlivoGenericResponse} object
+     * @promise {object} return {@link RetrievePowerpack} object
      * @fail {Error} return Error
      */
     create(name: string, params?: {}): Promise<CreatePowerpackResponse>;
diff --git a/types/rest/request-test.d.ts b/types/rest/request-test.d.ts
index 1f56632..c2221c1 100644
--- a/types/rest/request-test.d.ts
+++ b/types/rest/request-test.d.ts
@@ -1 +1 @@
-export function Request(config: any): (method: string, action: string, params: object) => Promise<any>;
+export function Request(config: any): (method: string, action: string, params: object) => Promise<any>;
\ No newline at end of file
diff --git a/types/rest/request.d.ts b/types/rest/request.d.ts
index 1f56632..c2221c1 100644
--- a/types/rest/request.d.ts
+++ b/types/rest/request.d.ts
@@ -1 +1 @@
-export function Request(config: any): (method: string, action: string, params: object) => Promise<any>;
+export function Request(config: any): (method: string, action: string, params: object) => Promise<any>;
\ No newline at end of file