diff --git a/modules/.eslintrc.json b/modules/.eslintrc.json
index 3b0938e4d..536b9c31e 100644
--- a/modules/.eslintrc.json
+++ b/modules/.eslintrc.json
@@ -9,6 +9,9 @@
 		"commonjs": true
 	},
 	"rules": {
-		"max-len": "off"
+		"max-len": "off",
+		"prefer-arrow-callback": "error",
+		"implicit-arrow-linebreak": "error",
+		"arrow-body-style": "error"
 	}
 }
diff --git a/modules/api/mw.echo.api.APIHandler.js b/modules/api/mw.echo.api.APIHandler.js
index c3a412094..17ff0efe9 100644
--- a/modules/api/mw.echo.api.APIHandler.js
+++ b/modules/api/mw.echo.api.APIHandler.js
@@ -158,7 +158,7 @@
 		}
 
 		return fetchNotifPromise
-			.fail( function () {
+			.fail( () => {
 				// Mark API error state
 				me.apiErrorState[ type ][ fetchingSource ] = true;
 			} );
diff --git a/modules/api/mw.echo.api.EchoApi.js b/modules/api/mw.echo.api.EchoApi.js
index c9ff29ba5..3225da040 100644
--- a/modules/api/mw.echo.api.EchoApi.js
+++ b/modules/api/mw.echo.api.EchoApi.js
@@ -61,9 +61,7 @@
 	 */
 	mw.echo.api.EchoApi.prototype.fetchUnreadNotificationPages = function ( sources ) {
 		return this.network.getApiHandler( 'local' ).fetchUnreadNotificationPages( sources )
-			.then( function ( data ) {
-				return OO.getProp( data, 'query', 'unreadnotificationpages' );
-			} );
+			.then( ( data ) => OO.getProp( data, 'query', 'unreadnotificationpages' ) );
 	};
 
 	/**
@@ -162,9 +160,7 @@
 			!!isForced,
 			this.convertFiltersToAPIParams( filters )
 		) )
-			.then( function ( result ) {
-				return OO.getProp( result.query, 'notifications' );
-			} );
+			.then( ( result ) => OO.getProp( result.query, 'notifications' ) );
 	};
 
 	/**
@@ -191,9 +187,7 @@
 			isForced,
 			this.convertFiltersToAPIParams( filters )
 		) )
-			.then( function ( result ) {
-				return OO.getProp( result.query, 'notifications' );
-			} );
+			.then( ( result ) => OO.getProp( result.query, 'notifications' ) );
 	};
 
 	/**
@@ -208,7 +202,7 @@
 	mw.echo.api.EchoApi.prototype.fetchNotificationGroups = function ( sourceArray, type, bundle ) {
 		const overrideParams = { notcrosswikisummary: false, notbundle: bundle };
 		return this.network.getApiHandler( 'local' ).fetchNotifications( type, sourceArray, true, overrideParams )
-			.then( function ( result ) {
+			.then( ( result ) => {
 				const items = OO.getProp( result, 'query', 'notifications', 'list' ),
 					groups = {};
 
diff --git a/modules/api/mw.echo.api.LocalAPIHandler.js b/modules/api/mw.echo.api.LocalAPIHandler.js
index c812bc02b..eb4689020 100644
--- a/modules/api/mw.echo.api.LocalAPIHandler.js
+++ b/modules/api/mw.echo.api.LocalAPIHandler.js
@@ -46,9 +46,7 @@
 			type: type.length === 1 ? type[ 0 ] : 'all',
 			timestampFormat: 'ISO_8601'
 		} )
-			.then( function ( data ) {
-				return data.query.echomarkseen.timestamp;
-			} );
+			.then( ( data ) => data.query.echomarkseen.timestamp );
 	};
 
 	/**
@@ -72,9 +70,7 @@
 		}
 
 		return this.api.postWithToken( 'csrf', data )
-			.then( function ( result ) {
-				return OO.getProp( result.query, 'echomarkread', type, 'rawcount' ) || 0;
-			} );
+			.then( ( result ) => OO.getProp( result.query, 'echomarkread', type, 'rawcount' ) || 0 );
 	};
 
 	/**
@@ -124,7 +120,7 @@
 		}
 
 		return this.api.get( apiData )
-			.then( function ( result ) {
+			.then( ( result ) => {
 				if ( type === 'message' || type === 'alert' ) {
 					return OO.getProp( result.query, 'notifications', normalizedType, 'rawcount' ) || 0;
 				} else {
diff --git a/modules/controller/mw.echo.Controller.js b/modules/controller/mw.echo.Controller.js
index 4b3c2fe13..2577d8e1b 100644
--- a/modules/controller/mw.echo.Controller.js
+++ b/modules/controller/mw.echo.Controller.js
@@ -85,7 +85,7 @@
 			sourcePageModel = filterModel.getSourcePagesModel();
 
 		return this.api.fetchUnreadNotificationPages()
-			.then( function ( data ) {
+			.then( ( data ) => {
 				const result = {},
 					foreignSources = {};
 
@@ -132,7 +132,7 @@
 				titles: filters.getSourcePagesModel().getGroupedPagesForCurrentTitle()
 			}
 		)
-			.then( function ( data ) {
+			.then( ( data ) => {
 				const dateItemIds = {},
 					dateItems = {},
 					models = {};
@@ -223,12 +223,10 @@
 			} )
 			.then(
 				null,
-				function ( errCode, errObj ) {
-					return {
-						errCode: errCode,
-						errInfo: OO.getProp( errObj, 'error', 'info' )
-					};
-				}
+				( errCode, errObj ) => ( {
+					errCode: errCode,
+					errInfo: OO.getProp( errObj, 'error', 'info' )
+				} )
 			);
 	};
 	/**
@@ -259,7 +257,7 @@
 		return this.api.fetchNotifications( this.manager.getTypeString(), 'local', !!isForced, { unreadFirst: true, bundle: true } /* filters */ )
 			.then(
 				// Success
-				function ( data ) {
+				( data ) => {
 					const allModels = { local: localListModel },
 						createBundledNotification = function ( modelName, rawBundledNotifData ) {
 							const bundleNotifData = controller.createNotificationData( rawBundledNotifData );
@@ -346,7 +344,7 @@
 					return idArray;
 				},
 				// Failure
-				function ( errCode, errObj ) {
+				( errCode, errObj ) => {
 					if ( !controller.manager.getNotificationModel( 'local' ) ) {
 						// Update the controller
 						controller.manager.setNotificationModels( { local: localListModel } );
@@ -457,7 +455,7 @@
 
 		source = source || this.manager.getFiltersModel().getSourcePagesModel().getCurrentSource();
 
-		this.manager.getNotificationsBySource( source ).forEach( function ( notification ) {
+		this.manager.getNotificationsBySource( source ).forEach( ( notification ) => {
 			if ( !notification.isRead() ) {
 				itemIds.push( ...notification.getAllIds() );
 				notification.toggleRead( true );
@@ -494,7 +492,7 @@
 		const readState = this.manager.getFiltersModel().getReadState(),
 			modelItems = {};
 
-		this.manager.getLocalNotifications().forEach( function ( notification ) {
+		this.manager.getLocalNotifications().forEach( ( notification ) => {
 			if ( !notification.isRead() ) {
 				notification.toggleRead( true );
 
@@ -538,7 +536,7 @@
 
 		return this.api.fetchNotificationGroups( xwikiModel.getSourceNames(), this.manager.getTypeString(), true )
 			.then(
-				function ( groupList ) {
+				( groupList ) => {
 					for ( const group in groupList ) {
 						const listModel = xwikiModel.getItemBySource( group );
 						const groupItems = groupList[ group ];
@@ -559,14 +557,12 @@
 						listModel.setItems( items );
 					}
 				},
-				function ( errCode, errObj ) {
-					return {
-						errCode: errCode,
-						errInfo: errCode === 'http' ?
-							mw.msg( 'echo-api-failure-cross-wiki' ) :
-							OO.getProp( errObj, 'error', 'info' )
-					};
-				}
+				( errCode, errObj ) => ( {
+					errCode: errCode,
+					errInfo: errCode === 'http' ?
+						mw.msg( 'echo-api-failure-cross-wiki' ) :
+						OO.getProp( errObj, 'error', 'info' )
+				} )
 			);
 	};
 
@@ -608,7 +604,7 @@
 			// to reflect the new pagination? etc.
 		}
 
-		items.forEach( function ( notification ) {
+		items.forEach( ( notification ) => {
 			allIds.push( ...notification.getAllIds() );
 			if ( readState === 'all' ) {
 				notification.toggleRead( isRead );
@@ -652,7 +648,7 @@
 		// Update pagination count
 		this.manager.updateCurrentPageItemCount();
 
-		notifs.forEach( function ( notif ) {
+		notifs.forEach( ( notif ) => {
 			allIds.push( ...notif.getAllIds() );
 		} );
 		this.manager.getUnreadCounter().estimateChange( -allIds.length );
@@ -677,7 +673,7 @@
 		this.manager.getUnreadCounter().estimateChange( -xwikiModel.getCount() );
 
 		return this.api.fetchNotificationGroups( xwikiModel.getSourceNames(), this.manager.getTypeString() )
-			.then( function ( groupList ) {
+			.then( ( groupList ) => {
 				const promises = [];
 
 				for ( const group in groupList ) {
@@ -736,7 +732,7 @@
 			// will be updated globally
 			this.manager.getFiltersModel().getSourcePagesModel().getCurrentSource()
 		)
-			.then( function ( time ) {
+			.then( ( time ) => {
 				controller.manager.getSeenTimeModel().setSeenTime( time );
 			} );
 	};
diff --git a/modules/ext.echo.centralauth.js b/modules/ext.echo.centralauth.js
index a1e50658e..6b467e365 100644
--- a/modules/ext.echo.centralauth.js
+++ b/modules/ext.echo.centralauth.js
@@ -1,7 +1,7 @@
 /*
  * Loads Echo on CentralAuth autologin
  */
-mw.hook( 'centralauth-p-personal-reset' ).add( function () {
+mw.hook( 'centralauth-p-personal-reset' ).add( () => {
 	mw.loader.using( [
 		'ext.echo.init',
 		'ext.echo.styles.badge',
diff --git a/modules/ext.echo.init.js b/modules/ext.echo.init.js
index 89ec47b85..90c1ebcd9 100644
--- a/modules/ext.echo.init.js
+++ b/modules/ext.echo.init.js
@@ -23,7 +23,7 @@ function initDesktop() {
 	}
 
 	// Activate OOUI
-	$( function () {
+	$( () => {
 		const maxNotificationCount = require( './config.json' ).EchoMaxNotificationCount,
 			pollingRate = require( './config.json' ).EchoPollForUpdates,
 			documentTitle = document.title,
@@ -73,7 +73,7 @@ function initDesktop() {
 		 */
 		function showNotificationSnippet( modelManager, highestNotifTime ) {
 			let highestTime = highestNotifTime;
-			modelManager.getLocalNotifications().forEach( function ( notificationItem ) {
+			modelManager.getLocalNotifications().forEach( ( notificationItem ) => {
 				const timestampAsDate = new Date( notificationItem.timestamp );
 				if ( timestampAsDate > highestNotifTime ) {
 					if ( timestampAsDate > highestTime ) {
@@ -95,7 +95,7 @@ function initDesktop() {
 		 * @param {mw.echo.ui.NotificationBadgeWidget} badgeWidget
 		 */
 		function updateBadgeState( modelManager, badgeWidget ) {
-			modelManager.getLocalNotifications().forEach( function ( notificationItem ) {
+			modelManager.getLocalNotifications().forEach( ( notificationItem ) => {
 				if ( !notificationItem.isSeen() ) {
 					badgeWidget.updateBadgeSeenState( true );
 				}
@@ -129,7 +129,7 @@ function initDesktop() {
 			// This part executes only once, either when header icons are clicked or after completion of 60secs whichever occur first.
 			const echoApi = new mw.echo.api.EchoApi();
 
-			loadingPromise = mw.loader.using( 'ext.echo.ui.desktop' ).then( function () {
+			loadingPromise = mw.loader.using( 'ext.echo.ui.desktop' ).then( () => {
 
 				// Overlay
 				mw.echo.ui.$overlay.appendTo( document.body );
@@ -155,15 +155,15 @@ function initDesktop() {
 				// Replace the link button with the ooui button
 				$existingAlertLink.parent().replaceWith( mw.echo.ui.alertWidget.$element );
 
-				alertModelManager.on( 'allTalkRead', function () {
+				alertModelManager.on( 'allTalkRead', () => {
 					// If there was a talk page notification, get rid of it
 					$( '#pt-talk-alert' ).remove();
 				} );
 
 				// listen to event countChange and change title only if polling rate is non-zero
 				if ( isLivePollingFeatureEnabledOnWiki() ) {
-					alertModelManager.getUnreadCounter().on( 'countChange', function ( count ) {
-						alertController.fetchLocalNotifications().then( function () {
+					alertModelManager.getUnreadCounter().on( 'countChange', ( count ) => {
+						alertController.fetchLocalNotifications().then( () => {
 							updateBadgeState( alertModelManager, mw.echo.ui.alertWidget );
 							if ( userHasOptedInToLiveNotifications() ) {
 								latestAlertNotifTime = showNotificationSnippet( alertModelManager, latestAlertNotifTime );
@@ -199,8 +199,8 @@ function initDesktop() {
 
 					// listen to event countChange and change title only if polling rate is non-zero
 					if ( isLivePollingFeatureEnabledOnWiki() ) {
-						messageModelManager.getUnreadCounter().on( 'countChange', function ( count ) {
-							messageController.fetchLocalNotifications().then( function () {
+						messageModelManager.getUnreadCounter().on( 'countChange', ( count ) => {
+							messageController.fetchLocalNotifications().then( () => {
 								updateBadgeState( messageModelManager, mw.echo.ui.messageWidget );
 								if ( userHasOptedInToLiveNotifications() ) {
 									latestMessageNotifTime = showNotificationSnippet( messageModelManager, latestMessageNotifTime );
@@ -234,15 +234,15 @@ function initDesktop() {
 			// Fire the notification API requests
 			const echoApi = new mw.echo.api.EchoApi();
 			echoApi.fetchNotifications( clickedSection )
-				.then( function ( data ) {
+				.then( ( data ) => {
 					mw.track( 'timing.MediaWiki.echo.overlay.api', mw.now() - timeOfClick );
 					return data;
 				} );
 
-			loadEcho().then( function () {
+			loadEcho().then( () => {
 				// Now that the module loaded, show the popup
 				const selectedWidget = clickedSection === 'alert' ? mw.echo.ui.alertWidget : mw.echo.ui.messageWidget;
-				selectedWidget.once( 'finishLoading', function () {
+				selectedWidget.once( 'finishLoading', () => {
 					// Log timing after notifications are shown
 					mw.track( 'timing.MediaWiki.echo.overlay', mw.now() - timeOfClick );
 				} );
@@ -255,7 +255,7 @@ function initDesktop() {
 					// The other part is the 'echo.unseen' counter, see EchoHooks::onSkinTemplateNavigationUniversal().
 					mw.track( 'counter.MediaWiki.echo.unseen.click' );
 				}
-			}, function () {
+			}, () => {
 				// Un-dim badge if loading failed
 				$badge.removeClass( 'mw-echo-notifications-badge-dimmed' );
 			} );
@@ -288,13 +288,13 @@ function initDesktop() {
  */
 function initMobile() {
 	if ( !mw.user.isAnon() ) {
-		mw.loader.using( [ 'ext.echo.mobile', 'mobile.startup' ] ).then( function ( require ) {
+		mw.loader.using( [ 'ext.echo.mobile', 'mobile.startup' ] ).then( ( require ) => {
 			require( 'ext.echo.mobile' ).init();
 		} );
 	}
 }
 
-$( function () {
+$( () => {
 	if ( mw.config.get( 'wgMFMode' ) ) {
 		initMobile();
 	} else {
diff --git a/modules/mobile/list.js b/modules/mobile/list.js
index 4ad7f72a3..52f8527bc 100644
--- a/modules/mobile/list.js
+++ b/modules/mobile/list.js
@@ -53,27 +53,27 @@ function notificationsList( echo, markAllReadButton, onCountChange ) {
 	} );
 
 	// Events
-	unreadCounter.on( 'countChange', function ( count ) {
+	unreadCounter.on( 'countChange', ( count ) => {
 		onCountChange(
 			controller.manager.getUnreadCounter().getCappedNotificationCount( count )
 		);
 		markAsReadHandler();
 	} );
-	markAllReadButton.on( 'click', function () {
+	markAllReadButton.on( 'click', () => {
 		const numNotifications = controller.manager.getLocalUnread().length;
 
 		controller.markLocalNotificationsRead()
-			.then( function () {
+			.then( () => {
 				mw.notify( mw.msg( 'echo-mark-all-as-read-confirmation', numNotifications ) );
 				markAllReadButton.toggle( false );
-			}, function () {
+			}, () => {
 				markAllReadButton.toggle( false );
 			} );
 	} );
 
 	return promisedView(
 		// Populate notifications
-		wrapperWidget.populate().then( function () {
+		wrapperWidget.populate().then( () => {
 			controller.updateSeenTime();
 			markAsReadHandler();
 			// Connect event here as we know that everything loaded correctly
diff --git a/modules/mobile/notifications.js b/modules/mobile/notifications.js
index acc1ceb97..70bad056d 100644
--- a/modules/mobile/notifications.js
+++ b/modules/mobile/notifications.js
@@ -29,7 +29,7 @@ function init() {
 
 	function showNotificationOverlay() {
 		const overlay = notificationsOverlay(
-			function ( exit ) {
+			( exit ) => {
 				onCloseNotificationsOverlay();
 				exit();
 			} );
@@ -41,7 +41,7 @@ function init() {
 	let initialized = false;
 	// Once the DOM is loaded add the overlay and overlay manager. Minerva will handle the
 	// notification button that will link to Special:Notifications.
-	$( function () {
+	$( () => {
 		overlayManager.add( /^\/notifications$/, showNotificationOverlay );
 
 		/**
@@ -73,7 +73,7 @@ function init() {
 		// The code is bundled here since it makes use of loadModuleScript. This also allows
 		// the possibility of invoking the filter from outside the Special page in future.
 		// Once the 'ext.echo.special.onInitialize' hook has fired, load notification filter.
-		mw.hook( 'ext.echo.special.onInitialize' ).add( function () {
+		mw.hook( 'ext.echo.special.onInitialize' ).add( () => {
 			// eslint-disable-next-line no-jquery/no-global-selector
 			const $crossWikiUnreadFilter = $( '.mw-echo-ui-crossWikiUnreadFilterWidget' ),
 				// eslint-disable-next-line no-jquery/no-global-selector
@@ -90,7 +90,7 @@ function init() {
 			addFilterButton();
 
 			// setup route
-			overlayManager.add( /^\/notifications-filter$/, function () {
+			overlayManager.add( /^\/notifications-filter$/, () => {
 				onOpenNotificationsOverlay();
 				return notificationsFilterOverlay( {
 					onBeforeExit: function ( exit ) {
diff --git a/modules/mobile/overlay.js b/modules/mobile/overlay.js
index ccff7b6d3..b890ee8bf 100644
--- a/modules/mobile/overlay.js
+++ b/modules/mobile/overlay.js
@@ -45,7 +45,7 @@ function onCountChange( count ) {
  */
 function notificationsOverlay( onBeforeExit ) {
 	let markAllReadButton;
-	const oouiPromise = mw.loader.using( 'oojs-ui' ).then( function () {
+	const oouiPromise = mw.loader.using( 'oojs-ui' ).then( () => {
 		markAllReadButton = new OO.ui.ButtonWidget( {
 			icon: 'checkAll'
 		} );
@@ -71,15 +71,13 @@ function notificationsOverlay( onBeforeExit ) {
 			isBorderBox: false,
 			className: 'overlay notifications-overlay navigation-drawer',
 			onBeforeExit: function ( exit ) {
-				onBeforeExit( function () {
+				onBeforeExit( () => {
 					onBeforeExitAnimation( overlay, exit );
 				} );
 			}
 		},
 		promisedView(
-			oouiPromise.then( function () {
-				return list( mw.echo, markAllReadButton, onCountChange );
-			} )
+			oouiPromise.then( () => list( mw.echo, markAllReadButton, onCountChange ) )
 		)
 	);
 	return overlay;
diff --git a/modules/model/mw.echo.dm.BundleNotificationItem.js b/modules/model/mw.echo.dm.BundleNotificationItem.js
index 66e6f7cbe..a5a8d00fb 100644
--- a/modules/model/mw.echo.dm.BundleNotificationItem.js
+++ b/modules/model/mw.echo.dm.BundleNotificationItem.js
@@ -15,7 +15,7 @@
 		// Parent constructor
 		mw.echo.dm.BundleNotificationItem.super.call( this, id, config );
 
-		this.getSecondaryUrls().forEach( function ( link ) {
+		this.getSecondaryUrls().forEach( ( link ) => {
 			// hack: put all secondary actions in the menu for now
 			// this is a temporary fix for
 			// - alignment of the labels
@@ -27,7 +27,7 @@
 		this.count = bundledNotificationModels.length;
 
 		// bundled notifications use the compact header and do not have icons
-		bundledNotificationModels.forEach( function ( bundled ) {
+		bundledNotificationModels.forEach( ( bundled ) => {
 			bundled.content.header = bundled.content.compactHeader;
 			delete bundled.iconURL;
 		} );
@@ -59,9 +59,7 @@
 	 * @return {boolean} Whether this bundle is completely read
 	 */
 	mw.echo.dm.BundleNotificationItem.prototype.isRead = function () {
-		return this.list.getItems().every( function ( item ) {
-			return item.isRead();
-		} );
+		return this.list.getItems().every( ( item ) => item.isRead() );
 	};
 
 	/**
@@ -102,7 +100,7 @@
 	 * @param {number} timestamp New seen timestamp
 	 */
 	mw.echo.dm.BundleNotificationItem.prototype.updateSeenState = function ( timestamp ) {
-		this.list.getItems().forEach( function ( notification ) {
+		this.list.getItems().forEach( ( notification ) => {
 			notification.toggleSeen(
 				notification.isRead() || notification.getTimestamp() < timestamp
 			);
@@ -126,9 +124,7 @@
 	 * @return {number[]}
 	 */
 	mw.echo.dm.BundleNotificationItem.prototype.getAllIds = function () {
-		return this.list.getItems().map( function ( item ) {
-			return item.getId();
-		} );
+		return this.list.getItems().map( ( item ) => item.getId() );
 	};
 
 	/**
diff --git a/modules/model/mw.echo.dm.CrossWikiNotificationItem.js b/modules/model/mw.echo.dm.CrossWikiNotificationItem.js
index f2373758e..289d957e2 100644
--- a/modules/model/mw.echo.dm.CrossWikiNotificationItem.js
+++ b/modules/model/mw.echo.dm.CrossWikiNotificationItem.js
@@ -122,8 +122,8 @@
 	 * @param {number} timestamp New seen timestamp
 	 */
 	mw.echo.dm.CrossWikiNotificationItem.prototype.updateSeenState = function ( timestamp ) {
-		this.getList().getItems().forEach( function ( source ) {
-			source.getItems().forEach( function ( notification ) {
+		this.getList().getItems().forEach( ( source ) => {
+			source.getItems().forEach( ( notification ) => {
 				notification.toggleSeen(
 					notification.isRead() || notification.getTimestamp() < timestamp
 				);
@@ -138,7 +138,7 @@
 	 */
 	mw.echo.dm.CrossWikiNotificationItem.prototype.getItems = function () {
 		let notifications = [];
-		this.list.getItems().forEach( function ( sourceList ) {
+		this.list.getItems().forEach( ( sourceList ) => {
 			notifications = notifications.concat( sourceList.getItems() );
 		} );
 
diff --git a/modules/model/mw.echo.dm.ModelManager.js b/modules/model/mw.echo.dm.ModelManager.js
index 34400e3c5..46cc8c901 100644
--- a/modules/model/mw.echo.dm.ModelManager.js
+++ b/modules/model/mw.echo.dm.ModelManager.js
@@ -433,7 +433,7 @@
 		source = source || 'local';
 
 		const notifications = [];
-		Object.keys( this.getAllNotificationModels() ).forEach( function ( modelName ) {
+		Object.keys( this.getAllNotificationModels() ).forEach( ( modelName ) => {
 			const model = manager.getNotificationModel( modelName );
 			if ( model.getSource() === source ) {
 				notifications.push( ...model.getItems() );
@@ -454,7 +454,7 @@
 
 		source = source || 'local';
 
-		Object.keys( this.getAllNotificationModels() ).forEach( function ( modelName ) {
+		Object.keys( this.getAllNotificationModels() ).forEach( ( modelName ) => {
 			const model = manager.getNotificationModel( modelName );
 			if ( model.getSource() === source ) {
 				modelIds.push( modelName );
diff --git a/modules/model/mw.echo.dm.NotificationGroupsList.js b/modules/model/mw.echo.dm.NotificationGroupsList.js
index a2b1fc61d..fef059aab 100644
--- a/modules/model/mw.echo.dm.NotificationGroupsList.js
+++ b/modules/model/mw.echo.dm.NotificationGroupsList.js
@@ -21,7 +21,7 @@
 		mw.echo.dm.NotificationGroupsList.super.call( this );
 
 		// Sorting callback
-		this.setSortingCallback( function ( a, b ) {
+		this.setSortingCallback( ( a, b ) => {
 			// Reverse sorting
 			if ( b.getTimestamp() < a.getTimestamp() ) {
 				return -1;
diff --git a/modules/model/mw.echo.dm.NotificationsList.js b/modules/model/mw.echo.dm.NotificationsList.js
index ff6c8ea73..b5f633e88 100644
--- a/modules/model/mw.echo.dm.NotificationsList.js
+++ b/modules/model/mw.echo.dm.NotificationsList.js
@@ -35,7 +35,7 @@
 		this.fallbackTimestamp = config.timestamp || 0;
 
 		// Sorting callback
-		this.setSortingCallback( config.sortingCallback || function ( a, b ) {
+		this.setSortingCallback( config.sortingCallback || ( ( a, b ) => {
 			if ( !a.isRead() && b.isRead() ) {
 				return -1; // Unread items are always above read items
 			} else if ( a.isRead() && !b.isRead() ) {
@@ -55,7 +55,7 @@
 
 			// Fallback on IDs
 			return b.getId() - a.getId();
-		} );
+		} ) );
 
 		// Events
 		this.aggregate( { update: 'itemUpdate' } );
@@ -215,9 +215,7 @@
 	 * @return {mw.echo.dm.NotificationItem[]} An array of matching items
 	 */
 	mw.echo.dm.NotificationsList.prototype.findByIds = function ( ids ) {
-		return this.getItems().filter( function ( item ) {
-			return ids.indexOf( item.getId() ) !== -1;
-		} );
+		return this.getItems().filter( ( item ) => ids.indexOf( item.getId() ) !== -1 );
 	};
 
 	/**
@@ -249,7 +247,7 @@
 	 * @param {string} timestamp New seen timestamp
 	 */
 	mw.echo.dm.NotificationsList.prototype.updateSeenState = function ( timestamp ) {
-		this.getItems().forEach( function ( notification ) {
+		this.getItems().forEach( ( notification ) => {
 			notification.toggleSeen(
 				notification.isRead() || notification.getTimestamp() < timestamp
 			);
diff --git a/modules/model/mw.echo.dm.SeenTimeModel.js b/modules/model/mw.echo.dm.SeenTimeModel.js
index 07c235044..613098b30 100644
--- a/modules/model/mw.echo.dm.SeenTimeModel.js
+++ b/modules/model/mw.echo.dm.SeenTimeModel.js
@@ -56,7 +56,7 @@
 		const model = this;
 
 		let hasChanged = false;
-		this.getTypes().forEach( function ( type ) {
+		this.getTypes().forEach( ( type ) => {
 			if ( model.seenTime[ type ] !== time ) {
 				model.seenTime[ type ] = time;
 				hasChanged = true;
diff --git a/modules/model/mw.echo.dm.UnreadNotificationCounter.js b/modules/model/mw.echo.dm.UnreadNotificationCounter.js
index d16c5d269..a789a4872 100644
--- a/modules/model/mw.echo.dm.UnreadNotificationCounter.js
+++ b/modules/model/mw.echo.dm.UnreadNotificationCounter.js
@@ -129,7 +129,7 @@
 			this.source,
 			this.type,
 			this.localOnly
-		) ).then( function ( actualCount ) {
+		) ).then( ( actualCount ) => {
 			model.setCount( actualCount, false );
 
 			return actualCount;
diff --git a/modules/special/ext.echo.special.js b/modules/special/ext.echo.special.js
index 2ab6a9c1a..986b8352c 100644
--- a/modules/special/ext.echo.special.js
+++ b/modules/special/ext.echo.special.js
@@ -4,7 +4,7 @@
 	/*!
 	 * Echo Special:Notifications page initialization
 	 */
-	$( function () {
+	$( () => {
 		const limitNotifications = 50,
 			links = mw.config.get( 'wgNotificationsSpecialPageLinks' ),
 			// FIXME: Use CSS transition
diff --git a/modules/ui/mw.echo.ui.BundleNotificationItemWidget.js b/modules/ui/mw.echo.ui.BundleNotificationItemWidget.js
index 7b8f650a9..8440b9530 100644
--- a/modules/ui/mw.echo.ui.BundleNotificationItemWidget.js
+++ b/modules/ui/mw.echo.ui.BundleNotificationItemWidget.js
@@ -23,7 +23,7 @@
 
 		this.listWidget = new mw.echo.ui.SortedListWidget(
 			// Sorting callback
-			function ( a, b ) {
+			( ( a, b ) => {
 				// Reverse sorting
 				if ( b.getTimestamp() < a.getTimestamp() ) {
 					return -1;
@@ -33,7 +33,7 @@
 
 				// Fallback on IDs
 				return b.getId() - a.getId();
-			},
+			} ),
 			// Config
 			{
 				classes: [ 'mw-echo-ui-bundleNotificationItemWidget-group' ],
@@ -50,11 +50,11 @@
 			.css( 'display', 'none' );
 
 		// Prevent clicks on the list padding area from activating the primary link
-		this.listWidget.$element.on( 'click', function ( e ) {
+		this.listWidget.$element.on( 'click', ( e ) => {
 			if ( e.target.closest( 'a' ) === this.$element[ 0 ] ) {
 				e.preventDefault();
 			}
-		}.bind( this ) );
+		} );
 
 		// Initialize closed
 		this.expanded = false;
@@ -115,16 +115,14 @@
 	 */
 	mw.echo.ui.BundleNotificationItemWidget.prototype.populateFromModel = function () {
 		const widget = this;
-		this.getList().addItems( this.model.getList().getItems().map( function ( singleNotifModel ) {
-			return new mw.echo.ui.SingleNotificationItemWidget(
-				widget.controller,
-				singleNotifModel,
-				{
-					$overlay: widget.$overlay,
-					bundle: true
-				}
-			);
-		} ) );
+		this.getList().addItems( this.model.getList().getItems().map( ( singleNotifModel ) => new mw.echo.ui.SingleNotificationItemWidget(
+			widget.controller,
+			singleNotifModel,
+			{
+				$overlay: widget.$overlay,
+				bundle: true
+			}
+		) ) );
 	};
 
 	/**
diff --git a/modules/ui/mw.echo.ui.CrossWikiNotificationItemWidget.js b/modules/ui/mw.echo.ui.CrossWikiNotificationItemWidget.js
index c3e981de0..337957774 100644
--- a/modules/ui/mw.echo.ui.CrossWikiNotificationItemWidget.js
+++ b/modules/ui/mw.echo.ui.CrossWikiNotificationItemWidget.js
@@ -31,7 +31,7 @@
 
 		this.listWidget = new mw.echo.ui.SortedListWidget(
 			// Sorting callback
-			function ( a, b ) {
+			( ( a, b ) => {
 				// Define the sorting order.
 				// This will go by the lists' timestamp, which in turn
 				// take the latest timestamp in their items
@@ -43,7 +43,7 @@
 
 				// Fallback on IDs
 				return b.getSource() - a.getSource();
-			},
+			} ),
 			// Config
 			{
 				classes: [ 'mw-echo-ui-crossWikiNotificationItemWidget-group' ],
@@ -232,7 +232,7 @@
 			// Query all sources
 			this.controller.fetchCrossWikiNotifications()
 				.catch(
-					function ( result ) {
+					( result ) => {
 						const loginPageTitle = mw.Title.newFromText( 'Special:UserLogin' );
 						// If failure, check if the failure is due to login
 						// so we can display a more comprehensive error
diff --git a/modules/ui/mw.echo.ui.CrossWikiUnreadFilterWidget.js b/modules/ui/mw.echo.ui.CrossWikiUnreadFilterWidget.js
index a70aac3a9..b6b0ca65d 100644
--- a/modules/ui/mw.echo.ui.CrossWikiUnreadFilterWidget.js
+++ b/modules/ui/mw.echo.ui.CrossWikiUnreadFilterWidget.js
@@ -17,7 +17,7 @@
 		// Parent constructor
 		mw.echo.ui.CrossWikiUnreadFilterWidget.super.call( this,
 			// Sorting callback
-			function ( a, b ) {
+			( a, b ) => {
 				// Local source is always first
 				if ( a.getSource() === 'local' ) {
 					return -1;
diff --git a/modules/ui/mw.echo.ui.DatedNotificationsWidget.js b/modules/ui/mw.echo.ui.DatedNotificationsWidget.js
index 4f80d0e02..a54247acb 100644
--- a/modules/ui/mw.echo.ui.DatedNotificationsWidget.js
+++ b/modules/ui/mw.echo.ui.DatedNotificationsWidget.js
@@ -30,14 +30,14 @@
 
 		this.listWidget = new mw.echo.ui.SortedListWidget(
 			// Sorting callback
-			function ( a, b ) {
+			( ( a, b ) => {
 				// Reverse sorting
 				if ( b.getTimestamp() < a.getTimestamp() ) {
 					return -1;
 				} else if ( b.getTimestamp() > a.getTimestamp() ) {
 					return 1;
 				}
-			},
+			} ),
 			// Config
 			{
 				classes: [ 'mw-echo-ui-datedNotificationsWidget-group' ],
@@ -118,7 +118,7 @@
 			groupWidgets.push( subgroupWidget );
 		}
 
-		this.getList().getItems().forEach( function ( widget ) {
+		this.getList().getItems().forEach( ( widget ) => {
 			// Destroy all available widgets
 			widget.destroy();
 		} );
diff --git a/modules/ui/mw.echo.ui.NotificationBadgeWidget.js b/modules/ui/mw.echo.ui.NotificationBadgeWidget.js
index a314178bd..9d1b7f41a 100644
--- a/modules/ui/mw.echo.ui.NotificationBadgeWidget.js
+++ b/modules/ui/mw.echo.ui.NotificationBadgeWidget.js
@@ -307,7 +307,7 @@
 		this.controller.fetchLocalNotifications( this.hasRunFirstTime )
 			.then(
 				// Success
-				function () {
+				() => {
 					if ( widget.popup.isVisible() ) {
 						// Fire initialization hook
 						mw.hook( 'ext.echo.popup.onInitialize' ).fire( widget.manager.getTypeString(), widget.controller );
@@ -317,7 +317,7 @@
 					}
 				},
 				// Failure
-				function ( errorObj ) {
+				( errorObj ) => {
 					if ( errorObj.errCode === 'notlogin-required' ) {
 						// Login required message
 						widget.notificationsWidget.resetLoadingOption( mw.msg( 'echo-notification-loginrequired' ) );
@@ -328,7 +328,7 @@
 				}
 			)
 			.then( this.emit.bind( this, 'finishLoading' ) )
-			.always( function () {
+			.always( () => {
 				widget.popup.clip();
 				// Pop pending
 				widget.popPending();
diff --git a/modules/ui/mw.echo.ui.NotificationItemWidget.js b/modules/ui/mw.echo.ui.NotificationItemWidget.js
index 00417cfcb..d5e1f5c15 100644
--- a/modules/ui/mw.echo.ui.NotificationItemWidget.js
+++ b/modules/ui/mw.echo.ui.NotificationItemWidget.js
@@ -243,7 +243,7 @@
 		// Send to controller
 		item.pushPending();
 		this.controller.performDynamicAction( actionData, this.getModel().getSource() )
-			.then( function () {
+			.then( () => {
 				const $title = $( '<p>' )
 						.addClass( 'mw-echo-ui-notificationItemWidget-notify-title' )
 						.append( $.parseHTML( messages.title ) ),
diff --git a/modules/ui/mw.echo.ui.NotificationsInboxWidget.js b/modules/ui/mw.echo.ui.NotificationsInboxWidget.js
index f05e0e34a..98ad77800 100644
--- a/modules/ui/mw.echo.ui.NotificationsInboxWidget.js
+++ b/modules/ui/mw.echo.ui.NotificationsInboxWidget.js
@@ -238,7 +238,7 @@
 		return fetchPromise
 			.then(
 				// Success
-				function () {
+				() => {
 					// Fire initialization hook
 					mw.hook( 'ext.echo.special.onInitialize' ).fire( widget.controller.manager.getTypeString(), widget.controller );
 
@@ -247,7 +247,7 @@
 					widget.controller.updateSeenTime();
 				},
 				// Failure
-				function ( errObj ) {
+				( errObj ) => {
 					let msg;
 					if ( errObj.errCode === 'notlogin-required' ) {
 						// Login required message
diff --git a/modules/ui/mw.echo.ui.NotificationsListWidget.js b/modules/ui/mw.echo.ui.NotificationsListWidget.js
index 31c19e8d8..ddf00997a 100644
--- a/modules/ui/mw.echo.ui.NotificationsListWidget.js
+++ b/modules/ui/mw.echo.ui.NotificationsListWidget.js
@@ -22,7 +22,7 @@
 		mw.echo.ui.NotificationsListWidget.super.call(
 			this,
 			// Sorting callback
-			function ( a, b ) {
+			( a, b ) => {
 				if ( !a.isRead() && b.isRead() ) {
 					return -1; // Unread items are always above read items
 				} else if ( a.isRead() && !b.isRead() ) {
diff --git a/modules/ui/mw.echo.ui.NotificationsWrapper.js b/modules/ui/mw.echo.ui.NotificationsWrapper.js
index 545f32029..f5fa276cc 100644
--- a/modules/ui/mw.echo.ui.NotificationsWrapper.js
+++ b/modules/ui/mw.echo.ui.NotificationsWrapper.js
@@ -69,7 +69,7 @@
 
 		this.pushPending();
 		return this.controller.fetchLocalNotifications( true )
-			.catch( function ( errorObj ) {
+			.catch( ( errorObj ) => {
 				if ( errorObj.errCode === 'notlogin-required' ) {
 					// Login required message
 					widget.notificationsWidget.resetLoadingOption( mw.msg( 'echo-notification-loginrequired' ) );
@@ -78,7 +78,7 @@
 					widget.notificationsWidget.resetLoadingOption( mw.msg( 'echo-api-failure' ) );
 				}
 			} )
-			.always( function () {
+			.always( () => {
 				widget.popPending();
 				widget.emit( 'finishLoading' );
 				widget.promiseRunning = false;
diff --git a/modules/ui/mw.echo.ui.PageFilterWidget.js b/modules/ui/mw.echo.ui.PageFilterWidget.js
index 887114f16..0e288b2f4 100644
--- a/modules/ui/mw.echo.ui.PageFilterWidget.js
+++ b/modules/ui/mw.echo.ui.PageFilterWidget.js
@@ -133,9 +133,7 @@
 
 		return OO.binarySearch(
 			this.items,
-			function ( otherItem ) {
-				return widget.sortingFunction( item, otherItem );
-			},
+			( otherItem ) => widget.sortingFunction( item, otherItem ),
 			true
 		);
 	};
diff --git a/modules/ui/mw.echo.ui.SortedListWidget.js b/modules/ui/mw.echo.ui.SortedListWidget.js
index 28b8b1640..58ed87f43 100644
--- a/modules/ui/mw.echo.ui.SortedListWidget.js
+++ b/modules/ui/mw.echo.ui.SortedListWidget.js
@@ -83,7 +83,7 @@
 			// fade out fake
 			// FIXME: Use CSS transition
 			// eslint-disable-next-line no-jquery/no-fade
-			fakeWidget.$element.fadeOut( 400, function () {
+			fakeWidget.$element.fadeOut( 400, () => {
 				// remove fake
 				widget.removeItems( [ fakeWidget ] );
 				// fade-in real item
diff --git a/modules/ui/mw.echo.ui.SubGroupListWidget.js b/modules/ui/mw.echo.ui.SubGroupListWidget.js
index f8551483e..c54c21356 100644
--- a/modules/ui/mw.echo.ui.SubGroupListWidget.js
+++ b/modules/ui/mw.echo.ui.SubGroupListWidget.js
@@ -31,7 +31,7 @@
 
 		this.listWidget = new mw.echo.ui.SortedListWidget(
 			// Sorting callback
-			config.sortingCallback || function ( a, b ) {
+			config.sortingCallback || ( ( a, b ) => {
 				// Reverse sorting
 				if ( b.getTimestamp() < a.getTimestamp() ) {
 					return -1;
@@ -41,7 +41,7 @@
 
 				// Fallback on IDs
 				return b.getId() - a.getId();
-			},
+			} ),
 			// Config
 			{
 				$overlay: this.$overlay,
diff --git a/tests/qunit/model/test_mw.echo.dm.BundleNotificationItem.js b/tests/qunit/model/test_mw.echo.dm.BundleNotificationItem.js
index 3df643884..08803fc53 100644
--- a/tests/qunit/model/test_mw.echo.dm.BundleNotificationItem.js
+++ b/tests/qunit/model/test_mw.echo.dm.BundleNotificationItem.js
@@ -1,6 +1,6 @@
 QUnit.module( 'ext.echo.dm - BundleNotificationItem' );
 
-QUnit.test( 'Constructing the model', function ( assert ) {
+QUnit.test( 'Constructing the model', ( assert ) => {
 	const bundledItems = [
 		new mw.echo.dm.NotificationItem( 0, { read: false, seen: false, timestamp: '201601010000' } ),
 		new mw.echo.dm.NotificationItem( 1, { read: false, seen: false, timestamp: '201601010100' } ),
@@ -44,9 +44,7 @@ QUnit.test( 'Constructing the model', function ( assert ) {
 		'Bundle has unseen items'
 	);
 
-	const findItems = bundle.findByIds( [ 1, 4 ] ).map( function ( item ) {
-		return item.getId();
-	} );
+	const findItems = bundle.findByIds( [ 1, 4 ] ).map( ( item ) => item.getId() );
 	assert.deepEqual(
 		findItems,
 		[ 4, 1 ],
@@ -54,7 +52,7 @@ QUnit.test( 'Constructing the model', function ( assert ) {
 	);
 } );
 
-QUnit.test( 'Managing a list of items', function ( assert ) {
+QUnit.test( 'Managing a list of items', ( assert ) => {
 	const bundledItems = [
 		new mw.echo.dm.NotificationItem( 0, { read: false, seen: false, timestamp: '201601010000' } ),
 		new mw.echo.dm.NotificationItem( 1, { read: false, seen: false, timestamp: '201601010100' } ),
@@ -77,7 +75,7 @@ QUnit.test( 'Managing a list of items', function ( assert ) {
 	);
 
 	// Mark all items as seen
-	bundledItems.forEach( function ( item ) {
+	bundledItems.forEach( ( item ) => {
 		item.toggleSeen( true );
 	} );
 
@@ -101,7 +99,7 @@ QUnit.test( 'Managing a list of items', function ( assert ) {
 	);
 
 	// Mark all items as read
-	bundledItems.forEach( function ( item ) {
+	bundledItems.forEach( ( item ) => {
 		item.toggleRead( true );
 	} );
 	assert.strictEqual(
diff --git a/tests/qunit/model/test_mw.echo.dm.CrossWikiNotificationItem.js b/tests/qunit/model/test_mw.echo.dm.CrossWikiNotificationItem.js
index ee93ab589..7f08160a4 100644
--- a/tests/qunit/model/test_mw.echo.dm.CrossWikiNotificationItem.js
+++ b/tests/qunit/model/test_mw.echo.dm.CrossWikiNotificationItem.js
@@ -26,7 +26,7 @@ QUnit.test.each( 'Constructing the model', {
 			getCount: 10
 		}
 	}
-}, function ( assert, data ) {
+}, ( assert, data ) => {
 	const defaults = {
 		getModelName: 'xwiki',
 		getSourceNames: [],
@@ -54,7 +54,7 @@ QUnit.test.each( 'Constructing the model', {
 	}
 } );
 
-QUnit.test( 'Managing notification lists', function ( assert ) {
+QUnit.test( 'Managing notification lists', ( assert ) => {
 	const model = new mw.echo.dm.CrossWikiNotificationItem( 1 );
 	const groupDefinitions = [
 		{
@@ -95,7 +95,7 @@ QUnit.test( 'Managing notification lists', function ( assert ) {
 	];
 
 	// Add groups to model
-	groupDefinitions.forEach( function ( def ) {
+	groupDefinitions.forEach( ( def ) => {
 		model.getList().addGroup(
 			def.name,
 			def.sourceData,
@@ -115,8 +115,8 @@ QUnit.test( 'Managing notification lists', function ( assert ) {
 	);
 
 	// Mark all items as seen except one
-	groupDefinitions.forEach( function ( def ) {
-		def.items.forEach( function ( item ) {
+	groupDefinitions.forEach( ( def ) => {
+		def.items.forEach( ( item ) => {
 			item.toggleSeen( true );
 		} );
 	} );
@@ -143,7 +143,7 @@ QUnit.test( 'Managing notification lists', function ( assert ) {
 	);
 } );
 
-QUnit.test( 'Update seen state', function ( assert ) {
+QUnit.test( 'Update seen state', ( assert ) => {
 	const model = new mw.echo.dm.CrossWikiNotificationItem( 1 );
 	const groupDefinitions = [
 		{
@@ -184,9 +184,7 @@ QUnit.test( 'Update seen state', function ( assert ) {
 	];
 
 	// Count all actual items
-	const numAllItems = groupDefinitions.reduce( function ( prev, curr ) {
-		return prev + curr.items.length;
-	}, 0 );
+	const numAllItems = groupDefinitions.reduce( ( prev, curr ) => prev + curr.items.length, 0 );
 
 	// Add groups to model
 	for ( let i = 0; i < groupDefinitions.length; i++ ) {
@@ -197,9 +195,7 @@ QUnit.test( 'Update seen state', function ( assert ) {
 		);
 	}
 
-	let numUnseenItems = model.getItems().filter( function ( item ) {
-		return !item.isSeen();
-	} ).length;
+	let numUnseenItems = model.getItems().filter( ( item ) => !item.isSeen() ).length;
 	assert.strictEqual(
 		numUnseenItems,
 		numAllItems,
@@ -209,9 +205,7 @@ QUnit.test( 'Update seen state', function ( assert ) {
 	// Update seen time to be bigger than 'foo' but smaller than the other groups
 	model.updateSeenState( '201601010400' );
 
-	numUnseenItems = model.getItems().filter( function ( item ) {
-		return !item.isSeen();
-	} ).length;
+	numUnseenItems = model.getItems().filter( ( item ) => !item.isSeen() ).length;
 	assert.strictEqual(
 		numUnseenItems,
 		numAllItems - groupDefinitions[ 0 ].items.length,
@@ -221,9 +215,7 @@ QUnit.test( 'Update seen state', function ( assert ) {
 	// Update seen time to be bigger than all
 	model.updateSeenState( '201701010000' );
 
-	numUnseenItems = model.getItems().filter( function ( item ) {
-		return !item.isSeen();
-	} ).length;
+	numUnseenItems = model.getItems().filter( ( item ) => !item.isSeen() ).length;
 	assert.strictEqual(
 		numUnseenItems,
 		0,
@@ -231,7 +223,7 @@ QUnit.test( 'Update seen state', function ( assert ) {
 	);
 } );
 
-QUnit.test( 'Emit discard event', function ( assert ) {
+QUnit.test( 'Emit discard event', ( assert ) => {
 	const results = [];
 	const model = new mw.echo.dm.CrossWikiNotificationItem( -1 );
 	const groupDefinitions = [
@@ -282,7 +274,7 @@ QUnit.test( 'Emit discard event', function ( assert ) {
 	}
 
 	// Listen to event
-	model.on( 'discard', function ( name ) {
+	model.on( 'discard', ( name ) => {
 		results.push( name );
 	} );
 
diff --git a/tests/qunit/model/test_mw.echo.dm.FiltersModel.js b/tests/qunit/model/test_mw.echo.dm.FiltersModel.js
index d09c62a67..2e622641b 100644
--- a/tests/qunit/model/test_mw.echo.dm.FiltersModel.js
+++ b/tests/qunit/model/test_mw.echo.dm.FiltersModel.js
@@ -21,7 +21,7 @@ QUnit.test.each( 'Constructing the model', {
 			getReadState: 'read'
 		}
 	}
-}, function ( assert, data ) {
+}, ( assert, data ) => {
 	const defaultValues = {
 		getReadState: 'all'
 	};
@@ -41,7 +41,7 @@ QUnit.test.each( 'Constructing the model', {
 	}
 } );
 
-QUnit.test( 'Changing filters', function ( assert ) {
+QUnit.test( 'Changing filters', ( assert ) => {
 	const model = new mw.echo.dm.FiltersModel();
 
 	assert.strictEqual(
@@ -72,12 +72,12 @@ QUnit.test( 'Changing filters', function ( assert ) {
 	);
 } );
 
-QUnit.test( '.setReadState() events', function ( assert ) {
+QUnit.test( '.setReadState() events', ( assert ) => {
 	const results = [];
 	const model = new mw.echo.dm.FiltersModel();
 
 	// Listen to update event
-	model.on( 'update', function () {
+	model.on( 'update', () => {
 		results.push( model.getReadState() );
 	} );
 
diff --git a/tests/qunit/model/test_mw.echo.dm.NotificationGroupsList.js b/tests/qunit/model/test_mw.echo.dm.NotificationGroupsList.js
index 1d06dae67..51eb5a2a0 100644
--- a/tests/qunit/model/test_mw.echo.dm.NotificationGroupsList.js
+++ b/tests/qunit/model/test_mw.echo.dm.NotificationGroupsList.js
@@ -1,6 +1,6 @@
 QUnit.module( 'ext.echo.dm - NotificationGroupsList' );
 
-QUnit.test( 'Constructing the model', function ( assert ) {
+QUnit.test( 'Constructing the model', ( assert ) => {
 	const model = new mw.echo.dm.NotificationGroupsList();
 
 	assert.strictEqual(
@@ -10,7 +10,7 @@ QUnit.test( 'Constructing the model', function ( assert ) {
 	);
 } );
 
-QUnit.test( 'Managing lists', function ( assert ) {
+QUnit.test( 'Managing lists', ( assert ) => {
 	const model = new mw.echo.dm.NotificationGroupsList();
 	const groupDefinitions = [
 		{
@@ -50,7 +50,7 @@ QUnit.test( 'Managing lists', function ( assert ) {
 		}
 	];
 
-	groupDefinitions.forEach( function ( def, i ) {
+	groupDefinitions.forEach( ( def, i ) => {
 		model.addGroup(
 			def.name,
 			def.sourceData,
@@ -95,7 +95,7 @@ QUnit.test( 'Managing lists', function ( assert ) {
 	);
 } );
 
-QUnit.test( 'Emitting discard event', function ( assert ) {
+QUnit.test( 'Emitting discard event', ( assert ) => {
 	const results = [];
 	const model = new mw.echo.dm.NotificationGroupsList();
 	const groups = {
@@ -121,7 +121,7 @@ QUnit.test( 'Emitting discard event', function ( assert ) {
 
 	// Listen to the event
 	model
-		.on( 'discard', function ( g ) {
+		.on( 'discard', ( g ) => {
 			results.push( g.getName() );
 		} );
 
diff --git a/tests/qunit/model/test_mw.echo.dm.NotificationItem.js b/tests/qunit/model/test_mw.echo.dm.NotificationItem.js
index 4a0b4768f..af3d2cca9 100644
--- a/tests/qunit/model/test_mw.echo.dm.NotificationItem.js
+++ b/tests/qunit/model/test_mw.echo.dm.NotificationItem.js
@@ -1,4 +1,4 @@
-QUnit.module( 'ext.echo.dm - NotificationItem', function ( hooks ) {
+QUnit.module( 'ext.echo.dm - NotificationItem', ( hooks ) => {
 	const fakeData = {
 		type: 'alert',
 		read: true,
@@ -67,7 +67,7 @@ QUnit.module( 'ext.echo.dm - NotificationItem', function ( hooks ) {
 				]
 			}
 		}
-	}, function ( assert, data ) {
+	}, ( assert, data ) => {
 		const defaultValues = {
 			getId: undefined,
 			getContentHeader: '',
@@ -94,7 +94,7 @@ QUnit.module( 'ext.echo.dm - NotificationItem', function ( hooks ) {
 		);
 
 		const methods = ( data.methods === 'all' ? Object.keys( expected ) : data.methods );
-		methods.forEach( function ( method ) {
+		methods.forEach( ( method ) => {
 			assert.deepEqual(
 				// Run the method
 				itemModel[ method ](),
@@ -106,12 +106,12 @@ QUnit.module( 'ext.echo.dm - NotificationItem', function ( hooks ) {
 		} );
 	} );
 
-	QUnit.test( 'Emitting update event', function ( assert ) {
+	QUnit.test( 'Emitting update event', ( assert ) => {
 		const results = [];
 		const itemModel = new mw.echo.dm.NotificationItem( 0, $.extend( true, {}, fakeData, { seen: false, read: false } ) );
 
 		// Listen to update event
-		itemModel.on( 'update', function () {
+		itemModel.on( 'update', () => {
 			results.push( [
 				itemModel.isRead(),
 				itemModel.isSeen()
diff --git a/tests/qunit/model/test_mw.echo.dm.NotificationsList.js b/tests/qunit/model/test_mw.echo.dm.NotificationsList.js
index 519011c6e..84ec6465b 100644
--- a/tests/qunit/model/test_mw.echo.dm.NotificationsList.js
+++ b/tests/qunit/model/test_mw.echo.dm.NotificationsList.js
@@ -22,7 +22,7 @@ QUnit.test.each( 'Constructing the model', {
 			isForeign: true
 		}
 	}
-}, function ( assert, data ) {
+}, ( assert, data ) => {
 	const defaultValues = {
 		getAllItemIds: [],
 		getAllItemIdsByType: [],
@@ -50,7 +50,7 @@ QUnit.test.each( 'Constructing the model', {
 	}
 } );
 
-QUnit.test( 'Handling notification items', function ( assert ) {
+QUnit.test( 'Handling notification items', ( assert ) => {
 	const model = new mw.echo.dm.NotificationsList( { timestamp: '200101010000' } );
 	const items = [
 		new mw.echo.dm.NotificationItem( 0, { type: 'alert', timestamp: '201609190000', read: false, seen: false } ),
@@ -137,7 +137,7 @@ QUnit.test( 'Handling notification items', function ( assert ) {
 
 } );
 
-QUnit.test( 'Intercepting events', function ( assert ) {
+QUnit.test( 'Intercepting events', ( assert ) => {
 	const model = new mw.echo.dm.NotificationsList();
 	const result = [];
 	const items = [
@@ -151,13 +151,13 @@ QUnit.test( 'Intercepting events', function ( assert ) {
 
 	// Listen to events
 	model
-		.on( 'update', function ( itms ) {
+		.on( 'update', ( itms ) => {
 			result.push( 'update:' + itms.length );
 		} )
-		.on( 'discard', function ( item ) {
+		.on( 'discard', ( item ) => {
 			result.push( 'discard:' + item.getId() );
 		} )
-		.on( 'itemUpdate', function ( item ) {
+		.on( 'itemUpdate', ( item ) => {
 			result.push( 'itemUpdate:' + item.getId() );
 		} );
 
diff --git a/tests/qunit/model/test_mw.echo.dm.PaginationModel.js b/tests/qunit/model/test_mw.echo.dm.PaginationModel.js
index a1c2bbbda..085bde7a1 100644
--- a/tests/qunit/model/test_mw.echo.dm.PaginationModel.js
+++ b/tests/qunit/model/test_mw.echo.dm.PaginationModel.js
@@ -17,7 +17,7 @@ QUnit.test.each( 'Constructing the model', {
 			getCurrentPageItemCount: 10
 		}
 	}
-}, function ( assert, data ) {
+}, ( assert, data ) => {
 	const defaultValues = {
 		getPageContinue: undefined,
 		getCurrPageIndex: 0,
@@ -45,12 +45,12 @@ QUnit.test.each( 'Constructing the model', {
 	}
 } );
 
-QUnit.test( 'Emitting update event', function ( assert ) {
+QUnit.test( 'Emitting update event', ( assert ) => {
 	const results = [];
 	const model = new mw.echo.dm.PaginationModel();
 
 	// Listen to update event
-	model.on( 'update', function () {
+	model.on( 'update', () => {
 		results.push( [
 			model.getCurrPageIndex(),
 			model.hasNextPage()
diff --git a/tests/qunit/model/test_mw.echo.dm.SeenTimeModel.js b/tests/qunit/model/test_mw.echo.dm.SeenTimeModel.js
index 4c5abcc8d..0ad606130 100644
--- a/tests/qunit/model/test_mw.echo.dm.SeenTimeModel.js
+++ b/tests/qunit/model/test_mw.echo.dm.SeenTimeModel.js
@@ -1,6 +1,6 @@
 QUnit.module( 'ext.echo.dm - SeenTimeModel' );
 
-QUnit.test( '.getTypes()', function ( assert ) {
+QUnit.test( '.getTypes()', ( assert ) => {
 	const model = new mw.echo.dm.SeenTimeModel();
 
 	assert.deepEqual(
@@ -10,7 +10,7 @@ QUnit.test( '.getTypes()', function ( assert ) {
 	);
 } );
 
-QUnit.test( '.setSeenTime() reflected', function ( assert ) {
+QUnit.test( '.setSeenTime() reflected', ( assert ) => {
 	let model;
 
 	model = new mw.echo.dm.SeenTimeModel();
@@ -32,12 +32,12 @@ QUnit.test( '.setSeenTime() reflected', function ( assert ) {
 	);
 } );
 
-QUnit.test( '.setSeenTime() events', function ( assert ) {
+QUnit.test( '.setSeenTime() events', ( assert ) => {
 	const results = [];
 	const model = new mw.echo.dm.SeenTimeModel();
 
 	// Attach a listener
-	model.on( 'update', function ( time ) {
+	model.on( 'update', ( time ) => {
 		results.push( time );
 	} );
 
diff --git a/tests/qunit/model/test_mw.echo.dm.SourcePagesModel.js b/tests/qunit/model/test_mw.echo.dm.SourcePagesModel.js
index 6fe1fdec7..28938e4dc 100644
--- a/tests/qunit/model/test_mw.echo.dm.SourcePagesModel.js
+++ b/tests/qunit/model/test_mw.echo.dm.SourcePagesModel.js
@@ -1,4 +1,4 @@
-QUnit.module( 'ext.echo.dm - SourcePagesModel', function () {
+QUnit.module( 'ext.echo.dm - SourcePagesModel', () => {
 	// Mock partial API response we feed into the model
 	const sources = {
 		local: {
@@ -75,7 +75,7 @@ QUnit.module( 'ext.echo.dm - SourcePagesModel', function () {
 		}
 	};
 
-	QUnit.test( 'Creating source-page map', function ( assert ) {
+	QUnit.test( 'Creating source-page map', ( assert ) => {
 		const model = new mw.echo.dm.SourcePagesModel();
 
 		model.setAllSources( sources );
diff --git a/tests/qunit/model/test_mw.echo.dm.UnreadNotificationCounter.js b/tests/qunit/model/test_mw.echo.dm.UnreadNotificationCounter.js
index dde2e71dd..f85b97dd4 100644
--- a/tests/qunit/model/test_mw.echo.dm.UnreadNotificationCounter.js
+++ b/tests/qunit/model/test_mw.echo.dm.UnreadNotificationCounter.js
@@ -4,7 +4,7 @@ QUnit.test.each( '.getCappedNotificationCount()', [
 	{ input: 5, output: 5 },
 	{ input: 20, output: 11 },
 	{ input: 10, output: 10 }
-], function ( assert, data ) {
+], ( assert, data ) => {
 	const model = new mw.echo.dm.UnreadNotificationCounter(
 		null,
 		'all', // type
@@ -17,7 +17,7 @@ QUnit.test.each( '.getCappedNotificationCount()', [
 	);
 } );
 
-QUnit.test( '.estimateChange()', function ( assert ) {
+QUnit.test( '.estimateChange()', ( assert ) => {
 	const model = new mw.echo.dm.UnreadNotificationCounter(
 		null,
 		'all', // type
@@ -48,7 +48,7 @@ QUnit.test( '.estimateChange()', function ( assert ) {
 	);
 } );
 
-QUnit.test( '.setCount()', function ( assert ) {
+QUnit.test( '.setCount()', ( assert ) => {
 	const results = [];
 	const model = new mw.echo.dm.UnreadNotificationCounter(
 		null,
@@ -57,7 +57,7 @@ QUnit.test( '.setCount()', function ( assert ) {
 	);
 
 	// Listen to event
-	model.on( 'countChange', function ( count ) {
+	model.on( 'countChange', ( count ) => {
 		results.push( count );
 	} );