diff --git a/extensions/mentions/composer.json b/extensions/mentions/composer.json
index a7d35c19f..a619da1ac 100644
--- a/extensions/mentions/composer.json
+++ b/extensions/mentions/composer.json
@@ -29,7 +29,7 @@
         "flarum-extension": {
             "title": "Mentions",
             "icon": {
-                "name": "fa fa-at",
+                "name": "fas fa-at",
                 "backgroundColor": "#539EC1",
                 "color": "#fff"
             }
diff --git a/extensions/mentions/js/forum/src/addMentionedByList.js b/extensions/mentions/js/forum/src/addMentionedByList.js
index 8768438b9..6a39a99cb 100644
--- a/extensions/mentions/js/forum/src/addMentionedByList.js
+++ b/extensions/mentions/js/forum/src/addMentionedByList.js
@@ -115,7 +115,7 @@ export default function addMentionedByList() {
       items.add('replies',
         <div className="Post-mentionedBy" config={config}>
           <span className="Post-mentionedBy-summary">
-            {icon('fa fa-reply')}
+            {icon('fas fa-reply')}
             {app.translator.transChoice('flarum-mentions.forum.post.mentioned_by' + (repliers[0].user() === app.session.user ? '_self' : '') + '_text', names.length, {
               count: names.length,
               users: punctuateSeries(names)
diff --git a/extensions/mentions/js/forum/src/components/PostMentionedNotification.js b/extensions/mentions/js/forum/src/components/PostMentionedNotification.js
index fd27f30de..b9ff41117 100644
--- a/extensions/mentions/js/forum/src/components/PostMentionedNotification.js
+++ b/extensions/mentions/js/forum/src/components/PostMentionedNotification.js
@@ -4,7 +4,7 @@ import punctuateSeries from 'flarum/helpers/punctuateSeries';
 
 export default class PostMentionedNotification extends Notification {
   icon() {
-    return 'fa fa-reply';
+    return 'fas fa-reply';
   }
 
   href() {
diff --git a/extensions/mentions/js/forum/src/components/PostQuoteButton.js b/extensions/mentions/js/forum/src/components/PostQuoteButton.js
index 0eb67bc68..950757c07 100644
--- a/extensions/mentions/js/forum/src/components/PostQuoteButton.js
+++ b/extensions/mentions/js/forum/src/components/PostQuoteButton.js
@@ -9,7 +9,7 @@ export default class PostQuoteButton extends Button {
     const content = extract(this.props, 'content');
 
     this.props.className = 'Button PostQuoteButton';
-    this.props.icon = 'fa fa-quote-left';
+    this.props.icon = 'fas fa-quote-left';
     this.props.children = app.translator.trans('flarum-mentions.forum.post.quote_button');
     this.props.onclick = () => {
       this.hide();
diff --git a/extensions/mentions/js/forum/src/components/UserMentionedNotification.js b/extensions/mentions/js/forum/src/components/UserMentionedNotification.js
index b768c48f8..16b84f0df 100644
--- a/extensions/mentions/js/forum/src/components/UserMentionedNotification.js
+++ b/extensions/mentions/js/forum/src/components/UserMentionedNotification.js
@@ -2,7 +2,7 @@ import Notification from 'flarum/components/Notification';
 
 export default class UserMentionedNotification extends Notification {
   icon() {
-    return 'fa fa-at';
+    return 'fas fa-at';
   }
 
   href() {
diff --git a/extensions/mentions/js/forum/src/main.js b/extensions/mentions/js/forum/src/main.js
index 3867b732c..a864473e2 100644
--- a/extensions/mentions/js/forum/src/main.js
+++ b/extensions/mentions/js/forum/src/main.js
@@ -41,13 +41,13 @@ app.initializers.add('flarum-mentions', function() {
   extend(NotificationGrid.prototype, 'notificationTypes', function(items) {
     items.add('postMentioned', {
       name: 'postMentioned',
-      icon: 'fa fa-reply',
+      icon: 'fas fa-reply',
       label: app.translator.trans('flarum-mentions.forum.settings.notify_post_mentioned_label')
     });
 
     items.add('userMentioned', {
       name: 'userMentioned',
-      icon: 'fa fa-at',
+      icon: 'fas fa-at',
       label: app.translator.trans('flarum-mentions.forum.settings.notify_user_mentioned_label')
     });
   });
@@ -61,7 +61,7 @@ app.initializers.add('flarum-mentions', function() {
         href: app.route('user.mentions', {username: user.username()}),
         name: 'mentions',
         children: [app.translator.trans('flarum-mentions.forum.user.mentions_link')],
-        icon: 'fa fa-at'
+        icon: 'fas fa-at'
       }),
       80
     );