diff --git a/dev/App/Admin.js b/dev/App/Admin.js
index 16e52eee2..72de5500a 100644
--- a/dev/App/Admin.js
+++ b/dev/App/Admin.js
@@ -6,7 +6,7 @@ import progressJs from 'progressJs';
 import { root } from 'Common/Links';
 import { getNotification } from 'Common/Translator';
 import { StorageResultType, Notification } from 'Common/Enums';
-import { pInt, isNormal, isArray, inArray, isUnd } from 'Common/Utils';
+import { pInt, isNormal, isArray, isUnd } from 'Common/Utils';
 
 import * as Settings from 'Storage/Settings';
 
@@ -168,7 +168,7 @@ class AdminApp extends AbstractApp {
 				if (
 					data &&
 					data.ErrorCode &&
-					-1 < inArray(pInt(data.ErrorCode), [Notification.LicensingServerIsUnavailable, Notification.LicensingExpired])
+					[Notification.LicensingServerIsUnavailable, Notification.LicensingExpired].includes(pInt(data.ErrorCode))
 				) {
 					LicenseStore.licenseError(getNotification(pInt(data.ErrorCode)));
 					LicenseStore.licensing(true);
diff --git a/dev/App/User.js b/dev/App/User.js
index fde5e903b..103a8fbde 100644
--- a/dev/App/User.js
+++ b/dev/App/User.js
@@ -8,7 +8,6 @@ import {
 	log,
 	has,
 	isArray,
-	inArray,
 	isUnd,
 	isNormal,
 	isPosNumeric,
@@ -342,7 +341,7 @@ class AppUser extends AbstractApp {
 			} else {
 				setFolderHash(FolderStore.currentFolderFullNameRaw(), '');
 
-				if (oData && -1 < inArray(oData.ErrorCode, [Notification.CantMoveMessage, Notification.CantCopyMessage])) {
+				if (oData && [Notification.CantMoveMessage, Notification.CantCopyMessage].includes(oData.ErrorCode)) {
 					window.alert(getNotification(oData.ErrorCode));
 				}
 			}
diff --git a/dev/Common/Selector.js b/dev/Common/Selector.js
index fb26047b3..35f17f812 100644
--- a/dev/Common/Selector.js
+++ b/dev/Common/Selector.js
@@ -3,7 +3,7 @@ import _ from '_';
 import key from 'key';
 import ko from 'ko';
 import { EventKeyCode } from 'Common/Enums';
-import { isArray, inArray, noop, noopTrue } from 'Common/Utils';
+import { isArray, noop, noopTrue } from 'Common/Utils';
 
 class Selector {
 	list;
@@ -159,7 +159,7 @@ class Selector {
 						mFocused = null;
 					}
 
-					if (0 < len && -1 < inArray(uid, aCheckedCache)) {
+					if (0 < len && aCheckedCache.includes(uid)) {
 						isChecked = true;
 						item.checked(true);
 						len -= 1;
@@ -181,7 +181,7 @@ class Selector {
 						if (null !== isNextFocused) {
 							getNext = false;
 							isNextFocused = _.find(aCache, (sUid) => {
-								if (getNext && -1 < inArray(sUid, uids)) {
+								if (getNext && uids.includes(sUid)) {
 									return sUid;
 								} else if (isNextFocused === sUid) {
 									getNext = true;
diff --git a/dev/Common/Translator.js b/dev/Common/Translator.js
index a5cbd6378..8dfc67bd6 100644
--- a/dev/Common/Translator.js
+++ b/dev/Common/Translator.js
@@ -3,7 +3,7 @@ import _ from '_';
 import $ from '$';
 import ko from 'ko';
 import { Notification, UploadErrorCode } from 'Common/Enums';
-import { pInt, isUnd, isNull, has, microtime, inArray } from 'Common/Utils';
+import { pInt, isUnd, isNull, has, microtime } from 'Common/Utils';
 import { $html, $htmlCL } from 'Common/Globals';
 import { reload as momentorReload } from 'Common/Momentor';
 import { langLink } from 'Common/Links';
@@ -274,7 +274,7 @@ export function reload(admin, language) {
 					() => {
 						reloadData();
 
-						const isRtl = -1 < inArray((language || '').toLowerCase(), ['ar', 'ar_sa', 'he', 'he_he', 'ur', 'ur_ir']);
+						const isRtl = ['ar', 'ar_sa', 'he', 'he_he', 'ur', 'ur_ir'].includes((language || '').toLowerCase());
 
 						$htmlCL.remove('rl-changing-language', 'rl-rtl', 'rl-ltr');
 							// $html.attr('dir', isRtl ? 'rtl' : 'ltr')
diff --git a/dev/Common/Utils.js b/dev/Common/Utils.js
index f3d20d23e..c8a4eeec4 100644
--- a/dev/Common/Utils.js
+++ b/dev/Common/Utils.js
@@ -10,8 +10,7 @@ import { Mime } from 'Common/Mime';
 import { jassl } from 'Common/Jassl';
 
 const trim = $.trim;
-const inArray = $.inArray;
-const isArray = _.isArray;
+const isArray = Array.isArray;
 const isObject = _.isObject;
 const isFunc = _.isFunction;
 const isUnd = _.isUndefined;
@@ -22,7 +21,7 @@ const noop = () => {}; // eslint-disable-line no-empty-function
 const noopTrue = () => true;
 const noopFalse = () => false;
 
-export { trim, inArray, isArray, isObject, isFunc, isUnd, isNull, has, bind, noop, noopTrue, noopFalse, jassl };
+export { trim, isArray, isObject, isFunc, isUnd, isNull, has, bind, noop, noopTrue, noopFalse, jassl };
 
 /**
  * @param {Function} func
@@ -935,7 +934,7 @@ export function folderListOptionsBuilder(
 				seporator: false,
 				disabled:
 					!oItem.selectable ||
-					-1 < inArray(oItem.fullNameRaw, aDisabled) ||
+					aDisabled.includes(oItem.fullNameRaw) ||
 					(fDisableCallback ? fDisableCallback(oItem) : false)
 			});
 		}
@@ -971,7 +970,7 @@ export function folderListOptionsBuilder(
 						seporator: false,
 						disabled:
 							!oItem.selectable ||
-							-1 < inArray(oItem.fullNameRaw, aDisabled) ||
+							aDisabled.includes(oItem.fullNameRaw) ||
 							(fDisableCallback ? fDisableCallback(oItem) : false)
 					});
 				}
diff --git a/dev/External/ko.js b/dev/External/ko.js
index 8db564aee..8f365c7a8 100644
--- a/dev/External/ko.js
+++ b/dev/External/ko.js
@@ -948,18 +948,17 @@ ko.extenders.posInterer = (target, defaultVal) => {
 };
 
 ko.extenders.limitedList = (target, limitedList) => {
-	const Utils = require('Common/Utils'),
-		result = ko
+	const result = ko
 			.computed({
 				read: target,
 				write: (newValue) => {
 					const currentValue = ko.unwrap(target),
 						list = ko.unwrap(limitedList);
 
-					if (Utils.isNonEmptyArray(list)) {
-						if (-1 < Utils.inArray(newValue, list)) {
+					if (Array.isArray(list) && 0 < list.length) {
+						if (list.includes(newValue)) {
 							target(newValue);
-						} else if (-1 < Utils.inArray(currentValue, list)) {
+						} else if (list.includes(currentValue, list)) {
 							target(currentValue + ' ');
 							target(currentValue);
 						} else {
diff --git a/dev/Model/Attachment.js b/dev/Model/Attachment.js
index 9555e7ddb..941b53a4a 100644
--- a/dev/Model/Attachment.js
+++ b/dev/Model/Attachment.js
@@ -4,7 +4,7 @@ import ko from 'ko';
 
 import { FileType } from 'Common/Enums';
 import { bAllowPdfPreview } from 'Common/Globals';
-import { trim, pInt, inArray, isNonEmptyArray, getFileExtension, friendlySize } from 'Common/Utils';
+import { trim, pInt, isNonEmptyArray, getFileExtension, friendlySize } from 'Common/Utils';
 import {
 	attachmentDownload,
 	attachmentPreview,
@@ -30,29 +30,28 @@ export const staticFileType = _.memoize((ext, mimeType) => {
 	const mimeTypeParts = mimeType.split('/');
 
 	switch (true) {
-		case 'image' === mimeTypeParts[0] || -1 < inArray(ext, ['png', 'jpg', 'jpeg', 'gif', 'bmp']):
+		case 'image' === mimeTypeParts[0] || ['png', 'jpg', 'jpeg', 'gif', 'bmp'].includes(ext):
 			result = FileType.Image;
 			break;
-		case 'audio' === mimeTypeParts[0] || -1 < inArray(ext, ['mp3', 'ogg', 'oga', 'wav']):
+		case 'audio' === mimeTypeParts[0] || ['mp3', 'ogg', 'oga', 'wav'].includes(ext):
 			result = FileType.Audio;
 			break;
-		case 'video' === mimeTypeParts[0] || -1 < inArray(ext, ['mkv', 'avi']):
+		case 'video' === mimeTypeParts[0] || ['mkv', 'avi'].includes(ext):
 			result = FileType.Video;
 			break;
-		case -1 < inArray(ext, ['php', 'js', 'css']):
+		case ['php', 'js', 'css'].includes(ext):
 			result = FileType.Code;
 			break;
-		case 'eml' === ext || -1 < inArray(mimeType, ['message/delivery-status', 'message/rfc822']):
+		case 'eml' === ext || ['message/delivery-status', 'message/rfc822'].includes(mimeType):
 			result = FileType.Eml;
 			break;
-		case ('text' === mimeTypeParts[0] && 'html' !== mimeTypeParts[1]) || -1 < inArray(ext, ['txt', 'log']):
+		case ('text' === mimeTypeParts[0] && 'html' !== mimeTypeParts[1]) || ['txt', 'log'].includes(ext):
 			result = FileType.Text;
 			break;
-		case 'text/html' === mimeType || -1 < inArray(ext, ['html']):
+		case 'text/html' === mimeType || ['html'].includes(ext):
 			result = FileType.Html;
 			break;
-		case -1 <
-			inArray(mimeTypeParts[1], [
+		case [
 				'zip',
 				'7z',
 				'tar',
@@ -70,21 +69,20 @@ export const staticFileType = _.memoize((ext, mimeType) => {
 				'x-zip-compressed',
 				'x-7z-compressed',
 				'x-rar-compressed'
-			]) || -1 < inArray(ext, ['zip', '7z', 'tar', 'rar', 'gzip', 'bzip', 'bzip2']):
+			].includes(mimeTypeParts[1]) || ['zip', '7z', 'tar', 'rar', 'gzip', 'bzip', 'bzip2'].includes(ext):
 			result = FileType.Archive;
 			break;
-		case -1 < inArray(mimeTypeParts[1], ['pdf', 'x-pdf']) || -1 < inArray(ext, ['pdf']):
+		case ['pdf', 'x-pdf'].includes(mimeTypeParts[1]) || ['pdf'].includes(ext):
 			result = FileType.Pdf;
 			break;
-		case -1 < inArray(mimeType, ['application/pgp-signature', 'application/pgp-keys']) ||
-			-1 < inArray(ext, ['asc', 'pem', 'ppk']):
+		case ['application/pgp-signature', 'application/pgp-keys'].includes(mimeType) ||
+			['asc', 'pem', 'ppk'].includes(ext):
 			result = FileType.Certificate;
 			break;
-		case -1 < inArray(mimeType, ['application/pkcs7-signature']) || -1 < inArray(ext, ['p7s']):
+		case ['application/pkcs7-signature'].includes(mimeType) || ['p7s'].includes(ext):
 			result = FileType.CertificateBin;
 			break;
-		case -1 <
-			inArray(mimeTypeParts[1], [
+		case [
 				'rtf',
 				'msword',
 				'vnd.msword',
@@ -92,11 +90,10 @@ export const staticFileType = _.memoize((ext, mimeType) => {
 				'vnd.openxmlformats-officedocument.wordprocessingml.template',
 				'vnd.ms-word.document.macroEnabled.12',
 				'vnd.ms-word.template.macroEnabled.12'
-			]):
+			].includes(mimeTypeParts[1]):
 			result = FileType.WordText;
 			break;
-		case -1 <
-			inArray(mimeTypeParts[1], [
+		case [
 				'excel',
 				'ms-excel',
 				'vnd.ms-excel',
@@ -106,11 +103,10 @@ export const staticFileType = _.memoize((ext, mimeType) => {
 				'vnd.ms-excel.template.macroEnabled.12',
 				'vnd.ms-excel.addin.macroEnabled.12',
 				'vnd.ms-excel.sheet.binary.macroEnabled.12'
-			]):
+			].includes(mimeTypeParts[1]):
 			result = FileType.Sheet;
 			break;
-		case -1 <
-			inArray(mimeTypeParts[1], [
+		case [
 				'powerpoint',
 				'ms-powerpoint',
 				'vnd.ms-powerpoint',
@@ -121,7 +117,7 @@ export const staticFileType = _.memoize((ext, mimeType) => {
 				'vnd.ms-powerpoint.presentation.macroEnabled.12',
 				'vnd.ms-powerpoint.template.macroEnabled.12',
 				'vnd.ms-powerpoint.slideshow.macroEnabled.12'
-			]):
+			].includes(mimeTypeParts[1]):
 			result = FileType.Presentation;
 			break;
 		// no default
diff --git a/dev/Model/Filter.js b/dev/Model/Filter.js
index 9ad5a6757..bbec81a7c 100644
--- a/dev/Model/Filter.js
+++ b/dev/Model/Filter.js
@@ -2,7 +2,7 @@ import _ from '_';
 import ko from 'ko';
 
 import { FilterRulesType, FiltersAction } from 'Common/Enums';
-import { pString, inArray, isNonEmptyArray, fakeMd5, delegateRunOnDestroy, windowResizeCallback } from 'Common/Utils';
+import { pString, isNonEmptyArray, fakeMd5, delegateRunOnDestroy, windowResizeCallback } from 'Common/Utils';
 import { i18n } from 'Common/Translator';
 import { getFolderFromCacheList } from 'Common/Cache';
 
@@ -152,21 +152,19 @@ class FilterModel extends AbstractModel {
 		}
 
 		if ('' === this.actionValue()) {
-			if (
-				-1 <
-				inArray(this.actionType(), [
+			if ([
 					FiltersAction.MoveTo,
 					FiltersAction.Forward,
 					FiltersAction.Reject,
 					FiltersAction.Vacation
-				])
+				].includes(this.actionType())
 			) {
 				this.actionValue.error(true);
 				return false;
 			}
 		}
 
-		if (FiltersAction.Forward === this.actionType() && -1 === this.actionValue().indexOf('@')) {
+		if (FiltersAction.Forward === this.actionType() && !this.actionValue().includes('@')) {
 			this.actionValue.error(true);
 			return false;
 		}
@@ -174,7 +172,7 @@ class FilterModel extends AbstractModel {
 		if (
 			FiltersAction.Vacation === this.actionType() &&
 			'' !== this.actionValueFourth() &&
-			-1 === this.actionValueFourth().indexOf('@')
+			!this.actionValueFourth().includes('@')
 		) {
 			this.actionValueFourth.error(true);
 			return false;
diff --git a/dev/Model/Message.js b/dev/Model/Message.js
index fb38149ed..e8bf9fa45 100644
--- a/dev/Model/Message.js
+++ b/dev/Model/Message.js
@@ -11,7 +11,6 @@ import { DATA_IMAGE_LAZY_PLACEHOLDER_PIC } from 'Common/Consts';
 
 import {
 	pInt,
-	inArray,
 	isArray,
 	isUnd,
 	trim,
@@ -253,7 +252,7 @@ class MessageModel extends AbstractModel {
 		if (json && 'Object/Message' === json['@Object']) {
 			priority = pInt(json.Priority);
 			this.priority(
-				-1 < inArray(priority, [MessagePriority.High, MessagePriority.Low]) ? priority : MessagePriority.Normal
+				[MessagePriority.High, MessagePriority.Low].includes(priority) ? priority : MessagePriority.Normal
 			);
 
 			this.folderFullNameRaw = json.Folder;
@@ -313,7 +312,7 @@ class MessageModel extends AbstractModel {
 		if (json && 'Object/Message' === json['@Object']) {
 			priority = pInt(json.Priority);
 			this.priority(
-				-1 < inArray(priority, [MessagePriority.High, MessagePriority.Low]) ? priority : MessagePriority.Normal
+				[MessagePriority.High, MessagePriority.Low].includes(priority) ? priority : MessagePriority.Normal
 			);
 
 			this.aDraftInfo = json.DraftInfo;
@@ -362,7 +361,7 @@ class MessageModel extends AbstractModel {
 					if (
 						'' !== attachment.cidWithOutTags &&
 						0 < this.foundedCIDs.length &&
-						0 <= inArray(attachment.cidWithOutTags, this.foundedCIDs)
+						this.foundedCIDs.includes(attachment.cidWithOutTags)
 					) {
 						attachment.isLinked = true;
 					}
diff --git a/dev/Promises/AbstractAjax.js b/dev/Promises/AbstractAjax.js
index c659e17c6..ed92a6fbd 100644
--- a/dev/Promises/AbstractAjax.js
+++ b/dev/Promises/AbstractAjax.js
@@ -2,7 +2,7 @@ import window from 'window';
 import $ from '$';
 
 import { ajax } from 'Common/Links';
-import { microtime, isUnd, isNormal, pString, pInt, inArray } from 'Common/Utils';
+import { microtime, isUnd, isNormal, pString, pInt } from 'Common/Utils';
 import { DEFAULT_AJAX_TIMEOUT, TOKEN_ERROR_LIMIT, AJAX_ERROR_LIMIT } from 'Common/Consts';
 import { StorageResultType, Notification } from 'Common/Enums';
 import { data as GlobalsData } from 'Common/Globals';
@@ -128,9 +128,7 @@ class AbstractAjaxPromises extends AbstractBasicPromises {
 				this.setTrigger(fTrigger, false);
 
 				if (errorData) {
-					if (
-						-1 <
-						inArray(errorData.ErrorCode, [
+					if ([
 							Notification.AuthError,
 							Notification.AccessError,
 							Notification.ConnectionError,
@@ -139,7 +137,7 @@ class AbstractAjaxPromises extends AbstractBasicPromises {
 							Notification.MailServerError,
 							Notification.UnknownNotification,
 							Notification.UnknownError
-						])
+						].includes(errorData.ErrorCode)
 					) {
 						GlobalsData.iAjaxErrorCount += 1;
 					}
diff --git a/dev/Remote/AbstractAjax.js b/dev/Remote/AbstractAjax.js
index efc6cd880..f7316544d 100644
--- a/dev/Remote/AbstractAjax.js
+++ b/dev/Remote/AbstractAjax.js
@@ -4,7 +4,7 @@ import $ from '$';
 
 import { TOKEN_ERROR_LIMIT, AJAX_ERROR_LIMIT, DEFAULT_AJAX_TIMEOUT } from 'Common/Consts';
 import { StorageResultType, Notification } from 'Common/Enums';
-import { inArray, pInt, pString, isUnd } from 'Common/Utils';
+import { pInt, pString, isUnd } from 'Common/Utils';
 import { data as GlobalsData } from 'Common/Globals';
 import { ajax } from 'Common/Links';
 import { runHook } from 'Common/Plugins';
@@ -32,9 +32,7 @@ class AbstractAjaxRemote {
 
 			if (StorageResultType.Success === sType && oData && !oData.Result) {
 				if (
-					oData &&
-					-1 <
-						inArray(oData.ErrorCode, [
+					oData && [
 							Notification.AuthError,
 							Notification.AccessError,
 							Notification.ConnectionError,
@@ -43,7 +41,7 @@ class AbstractAjaxRemote {
 							Notification.MailServerError,
 							Notification.UnknownNotification,
 							Notification.UnknownError
-						])
+						].includes(oData.ErrorCode)
 				) {
 					GlobalsData.iAjaxErrorCount += 1;
 				}
@@ -178,7 +176,7 @@ class AbstractAjaxRemote {
 			this.defaultResponse(fResultCallback, action, sType, oData, cached, params);
 		});
 
-		if (action && 0 < abortActions.length && -1 < inArray(action, abortActions)) {
+		if (action && 0 < abortActions.length && abortActions.includes(action)) {
 			if (this.oRequests[action]) {
 				this.oRequests[action].__aborted = true;
 				if (this.oRequests[action].abort) {
diff --git a/dev/Settings/Admin/Contacts.js b/dev/Settings/Admin/Contacts.js
index d6bdcb385..15603645c 100644
--- a/dev/Settings/Admin/Contacts.js
+++ b/dev/Settings/Admin/Contacts.js
@@ -1,7 +1,7 @@
 import _ from '_';
 import ko from 'ko';
 
-import { settingsSaveHelperSimpleFunction, defautOptionsAfterRender, inArray, trim, boolToAjax } from 'Common/Utils';
+import { settingsSaveHelperSimpleFunction, defautOptionsAfterRender, trim, boolToAjax } from 'Common/Utils';
 
 import { SaveSettingsStep, StorageResultType, Magics } from 'Common/Enums';
 import { i18n } from 'Common/Translator';
@@ -49,7 +49,7 @@ class ContactsAdminSettings {
 		this.contactsTypes = ko.observableArray([]);
 		this.contactsTypesOptions = ko.computed(() =>
 			_.map(this.contactsTypes(), (value) => {
-				const disabled = -1 === inArray(value, supportedTypes);
+				const disabled = supportedTypes.includes(value);
 				return {
 					'id': value,
 					'name': getTypeName(value) + (disabled ? ' (' + i18n('HINTS/NOT_SUPPORTED') + ')' : ''),
@@ -66,7 +66,7 @@ class ContactsAdminSettings {
 				read: this.contactsType,
 				write: (value) => {
 					if (value !== this.contactsType()) {
-						if (-1 < inArray(value, supportedTypes)) {
+						if (supportedTypes.includes(value)) {
 							this.contactsType(value);
 						} else if (0 < supportedTypes.length) {
 							this.contactsType('');
diff --git a/dev/Storage/Settings.js b/dev/Storage/Settings.js
index e4ecbabea..5eeaef011 100644
--- a/dev/Storage/Settings.js
+++ b/dev/Storage/Settings.js
@@ -1,5 +1,5 @@
 import window from 'window';
-import { isUnd, isNormal, isArray, inArray } from 'Common/Utils';
+import { isUnd, isNormal, isArray } from 'Common/Utils';
 
 let SETTINGS = window.__rlah_data() || null;
 SETTINGS = isNormal(SETTINGS) ? SETTINGS : {};
@@ -37,5 +37,5 @@ export function appSettingsGet(name) {
  */
 export function capa(name) {
 	const values = settingsGet('Capa');
-	return isArray(values) && isNormal(name) && -1 < inArray(name, values);
+	return isArray(values) && isNormal(name) && values.includes(name);
 }
diff --git a/dev/Stores/User/Message.js b/dev/Stores/User/Message.js
index eed66f84a..7f274d9a3 100644
--- a/dev/Stores/User/Message.js
+++ b/dev/Stores/User/Message.js
@@ -9,7 +9,6 @@ import {
 	trim,
 	isNormal,
 	isArray,
-	inArray,
 	pInt,
 	pString,
 	plainToHtml,
@@ -308,7 +307,7 @@ class MessageUserStore {
 			currentFolderFullNameRaw = FolderStore.currentFolderFullNameRaw(),
 			messages =
 				currentFolderFullNameRaw === fromFolderFullNameRaw
-					? _.filter(messageList, (item) => item && -1 < inArray(pInt(item.uid), uidForRemove))
+					? _.filter(messageList, (item) => item && uidForRemove.includes(pInt(item.uid)))
 					: [];
 
 		_.each(messages, (item) => {
@@ -499,7 +498,7 @@ class MessageUserStore {
 			message.folderFullNameRaw === data.Result.Folder
 		) {
 			const threads = message.threads();
-			if (message.uid !== data.Result.Uid && 1 < threads.length && -1 < inArray(data.Result.Uid, threads)) {
+			if (message.uid !== data.Result.Uid && 1 < threads.length && threads.includes(data.Result.Uid)) {
 				message = MessageModel.newInstanceFromJson(data.Result);
 				if (message) {
 					message.threads(threads);
diff --git a/dev/View/Popup/ComposeOpenPgp.js b/dev/View/Popup/ComposeOpenPgp.js
index 85a7d3d9a..99cbe529a 100644
--- a/dev/View/Popup/ComposeOpenPgp.js
+++ b/dev/View/Popup/ComposeOpenPgp.js
@@ -3,7 +3,7 @@ import $ from '$';
 import ko from 'ko';
 import key from 'key';
 
-import { inArray, pString, log, isUnd, trim, defautOptionsAfterRender } from 'Common/Utils';
+import { pString, log, isUnd, trim, defautOptionsAfterRender } from 'Common/Utils';
 
 import { Magics, KeyState } from 'Common/Enums';
 import { i18n } from 'Common/Translator';
@@ -64,7 +64,7 @@ class ComposeOpenPgpPopupView extends AbstractViewNext {
 
 		this.publicKeysOptions = ko.computed(() => {
 			const opts = _.map(PgpStore.openpgpkeysPublic(), (oKey, index) => {
-				if (-1 < inArray(oKey, this.encryptKeysView())) {
+				if (this.encryptKeysView().includes(oKey)) {
 					return null;
 				}
 				return _.map(oKey.users, (user) => ({
diff --git a/dev/View/Popup/Contacts.js b/dev/View/Popup/Contacts.js
index 986bcc37e..58f1a9534 100644
--- a/dev/View/Popup/Contacts.js
+++ b/dev/View/Popup/Contacts.js
@@ -19,7 +19,6 @@ import {
 import {
 	delegateRunOnDestroy,
 	computedPagenatorHelper,
-	inArray,
 	trim,
 	windowResizeCallback,
 	isNonEmptyArray,
@@ -101,11 +100,11 @@ class ContactsPopupView extends AbstractViewNext {
 		this.viewPropertiesNames = ko.computed(() =>
 			_.filter(
 				this.viewProperties(),
-				(property) => -1 < inArray(property.type(), [ContactPropertyType.FirstName, ContactPropertyType.LastName])
+				(property) => [ContactPropertyType.FirstName, ContactPropertyType.LastName].includes(property.type())
 			)
 		);
 		this.viewPropertiesOther = ko.computed(() =>
-			_.filter(this.viewProperties(), (property) => -1 < inArray(property.type(), [ContactPropertyType.Nick]))
+			_.filter(this.viewProperties(), (property) => [ContactPropertyType.Nick].includes(property.type()))
 		);
 
 		this.viewPropertiesEmails = ko.computed(() =>
diff --git a/dev/View/User/Login.js b/dev/View/User/Login.js
index 87ccd2ef9..ed27d40ff 100644
--- a/dev/View/User/Login.js
+++ b/dev/View/User/Login.js
@@ -10,7 +10,7 @@ import {
 	Notification
 } from 'Common/Enums';
 
-import { trim, inArray, convertLangName, triggerAutocompleteInputChange } from 'Common/Utils';
+import { trim, convertLangName, triggerAutocompleteInputChange } from 'Common/Utils';
 
 import { $win } from 'Common/Globals';
 import { getNotification, getNotificationFromResponse, reload as translatorReload } from 'Common/Translator';
@@ -225,7 +225,7 @@ class LoginUserView extends AbstractViewNext {
 							}
 						} else if (oData.ErrorCode) {
 							this.submitRequest(false);
-							if (-1 < inArray(oData.ErrorCode, [Notification.InvalidInputArgument])) {
+							if ([Notification.InvalidInputArgument].includes(oData.ErrorCode)) {
 								oData.ErrorCode = Notification.AuthError;
 							}
 
diff --git a/dev/View/User/MailBox/FolderList.js b/dev/View/User/MailBox/FolderList.js
index ed91c4ce3..bf491365d 100644
--- a/dev/View/User/MailBox/FolderList.js
+++ b/dev/View/User/MailBox/FolderList.js
@@ -58,7 +58,7 @@ class FolderListMailBoxUserView extends AbstractViewNext {
 			() =>
 				FolderStore.currentFolder() &&
 				FolderStore.currentFolder().isInbox() &&
-				-1 < trim(MessageStore.messageListSearch()).indexOf('is:flagged')
+				trim(MessageStore.messageListSearch()).includes('is:flagged')
 		);
 	}
 
diff --git a/dev/View/User/MailBox/MessageList.js b/dev/View/User/MailBox/MessageList.js
index 221924f25..cf0e3b3d3 100644
--- a/dev/View/User/MailBox/MessageList.js
+++ b/dev/View/User/MailBox/MessageList.js
@@ -22,7 +22,7 @@ import { UNUSED_OPTION_VALUE } from 'Common/Consts';
 
 import { bMobileDevice, popupVisibility, leftPanelDisabled, moveAction } from 'Common/Globals';
 
-import { noop, noopFalse, computedPagenatorHelper, draggablePlace, friendlySize, inArray, isUnd } from 'Common/Utils';
+import { noop, noopFalse, computedPagenatorHelper, draggablePlace, friendlySize, isUnd } from 'Common/Utils';
 
 import { mailBox, append } from 'Common/Links';
 import { Selector } from 'Common/Selector';
@@ -653,7 +653,7 @@ class MessageListMailBoxUserView extends AbstractViewNext {
 		const checked = this.messageListCheckedOrSelected();
 		if (currentMessage) {
 			const checkedUids = _.map(checked, (message) => message.uid);
-			if (0 < checkedUids.length && -1 < inArray(currentMessage.uid, checkedUids)) {
+			if (0 < checkedUids.length && checkedUids.includes(currentMessage.uid)) {
 				this.setAction(
 					currentMessage.folderFullNameRaw,
 					currentMessage.flagged() ? MessageSetAction.UnsetFlag : MessageSetAction.SetFlag,
diff --git a/dev/View/User/MailBox/MessageView.js b/dev/View/User/MailBox/MessageView.js
index a983fa2b5..aa16970c6 100644
--- a/dev/View/User/MailBox/MessageView.js
+++ b/dev/View/User/MailBox/MessageView.js
@@ -20,7 +20,6 @@ import {
 import { $htmlCL, leftPanelDisabled, keyScopeReal, useKeyboardShortcuts, moveAction } from 'Common/Globals';
 
 import {
-	inArray,
 	isNonEmptyArray,
 	trim,
 	noop,
@@ -135,7 +134,7 @@ class MessageViewMailBoxUserView extends AbstractViewNext {
 		);
 
 		this.downloadAsZipAllowed = ko.computed(
-			() => -1 < inArray('zip', this.attachmentsActions()) && this.allowAttachmnetControls()
+			() => this.attachmentsActions().includes('zip') && this.allowAttachmnetControls()
 		);
 
 		this.downloadAsZipLoading = ko.observable(false);
@@ -156,7 +155,7 @@ class MessageViewMailBoxUserView extends AbstractViewNext {
 			read: this.lastReplyAction_,
 			write: (value) => {
 				this.lastReplyAction_(
-					-1 === inArray(value, [ComposeType.Reply, ComposeType.ReplyAll, ComposeType.Forward])
+					[ComposeType.Reply, ComposeType.ReplyAll, ComposeType.Forward].includes(value)
 						? ComposeType.Reply
 						: value
 				);