diff --git a/ghost/admin/.lint-todo b/ghost/admin/.lint-todo
index 44ad70613c..3e598c38b5 100644
--- a/ghost/admin/.lint-todo
+++ b/ghost/admin/.lint-todo
@@ -1009,3 +1009,4 @@ remove|ember-template-lint|no-action|34|39|34|39|e65f48edccba27e52c1f8358a9795dc
 remove|ember-template-lint|no-action|50|35|50|35|7432725bd18c48f69bf22dc9487d14d25dc6c1b7|1662681600000|1673053200000|1678237200000|app/templates/signin.hbs
 remove|ember-template-lint|no-passed-in-event-handlers|33|28|33|28|5b371baf419f247953b91b626611cb831c524af3|1662681600000|1673053200000|1678237200000|app/templates/signin.hbs
 remove|ember-template-lint|no-passed-in-event-handlers|50|28|50|28|40caf07c7cebf6f4321c5b7e7f2f426b5c30217b|1662681600000|1673053200000|1678237200000|app/templates/signin.hbs
+remove|ember-template-lint|require-iframe-title|1|0|1|0|d1c9631d150af53ca33b16c8c280c9d815bf43da|1662681600000|1673053200000|1678237200000|app/components/gh-billing-iframe.hbs
diff --git a/ghost/admin/app/components/gh-billing-iframe.hbs b/ghost/admin/app/components/gh-billing-iframe.hbs
index 9ba092062c..5a0ed00241 100644
--- a/ghost/admin/app/components/gh-billing-iframe.hbs
+++ b/ghost/admin/app/components/gh-billing-iframe.hbs
@@ -1 +1 @@
-<iframe id="billing-frame" class="billing-frame" frameborder="0"></iframe>
\ No newline at end of file
+<iframe id="billing-frame" class="billing-frame" frameborder="0" title="Billing" ...attributes {{did-insert this.setup}}></iframe>
\ No newline at end of file
diff --git a/ghost/admin/app/components/gh-billing-iframe.js b/ghost/admin/app/components/gh-billing-iframe.js
index 05dd46e471..dd137c99a7 100644
--- a/ghost/admin/app/components/gh-billing-iframe.js
+++ b/ghost/admin/app/components/gh-billing-iframe.js
@@ -1,10 +1,10 @@
-import Component from '@ember/component';
-import classic from 'ember-classic-decorator';
+import Component from '@glimmer/component';
+import {action} from '@ember/object';
 import {htmlSafe} from '@ember/template';
 import {inject} from 'ghost-admin/decorators/inject';
 import {inject as service} from '@ember/service';
+import {tracked} from '@glimmer/tracking';
 
-@classic
 export default class GhBillingIframe extends Component {
     @service billing;
     @service ghostPaths;
@@ -13,36 +13,46 @@ export default class GhBillingIframe extends Component {
 
     @inject config;
 
-    isOwner = null;
-    fetchingSubscription = false;
+    @tracked isOwner = null;
+    @tracked fetchingSubscription = false;
 
-    didInsertElement() {
-        super.didInsertElement(...arguments);
+    willDestroy() {
+        super.willDestroy(...arguments);
+        window.removeEventListener('message', this.handleIframeMessage);
+    }
 
+    @action
+    setup() {
         this.billing.getBillingIframe().src = this.billing.getIframeURL();
+        window.addEventListener('message', this.handleIframeMessage);
+    }
 
-        window.addEventListener('message', (event) => {
-            // only process messages coming from the billing iframe
-            if (event?.data && this.billing.getIframeURL().includes(event?.origin)) {
-                if (event.data?.request === 'token') {
-                    this._handleTokenRequest();
-                }
+    @action
+    async handleIframeMessage(event) {
+        if (this.isDestroyed || this.isDestroying) {
+            return;
+        }
 
-                if (event.data?.request === 'forceUpgradeInfo') {
-                    this._handleForceUpgradeRequest();
-                }
-
-                if (event.data?.subscription) {
-                    this._handleSubscriptionUpdate(event.data);
-                }
+        // only process messages coming from the billing iframe
+        if (event?.data && this.billing.getIframeURL().includes(event?.origin)) {
+            if (event.data?.request === 'token') {
+                this._handleTokenRequest();
             }
-        });
+
+            if (event.data?.request === 'forceUpgradeInfo') {
+                this._handleForceUpgradeRequest();
+            }
+
+            if (event.data?.subscription) {
+                this._handleSubscriptionUpdate(event.data);
+            }
+        }
     }
 
     _handleTokenRequest() {
-        this.set('fetchingSubscription', false);
+        this.fetchingSubscription = false;
         let token;
-        const ghostIdentityUrl = this.get('ghostPaths.url').api('identities');
+        const ghostIdentityUrl = this.ghostPaths.url.api('identities');
 
         this.ajax.request(ghostIdentityUrl).then((response) => {
             token = response && response.identities && response.identities[0] && response.identities[0].token;
@@ -51,11 +61,11 @@ export default class GhBillingIframe extends Component {
                 response: token
             }, '*');
 
-            this.set('isOwner', true);
+            this.isOwner = true;
         }).catch((error) => {
             if (error.payload?.errors && error.payload.errors[0]?.type === 'NoPermissionError') {
                 // no permission means the current user requesting the token is not the owner of the site.
-                this.set('isOwner', false);
+                this.isOwner = false;
 
                 // Avoid letting the BMA waiting for a message and send an empty token response instead
                 this.billing.getBillingIframe().contentWindow.postMessage({
@@ -69,8 +79,8 @@ export default class GhBillingIframe extends Component {
 
         // NOTE: the handler is placed here to avoid additional logic to check if iframe has loaded
         //       receiving a 'token' request is an indication that page is ready
-        if (!this.fetchingSubscription && !this.billing.get('subscription') && token) {
-            this.set('fetchingSubscription', true);
+        if (!this.fetchingSubscription && !this.billing.subscription && token) {
+            this.fetchingSubscription = true;
             this.billing.getBillingIframe().contentWindow.postMessage({
                 query: 'getSubscription',
                 response: 'subscription'
@@ -100,8 +110,8 @@ export default class GhBillingIframe extends Component {
     }
 
     _handleSubscriptionUpdate(data) {
-        this.billing.set('subscription', data.subscription);
-        this.billing.set('checkoutRoute', data?.checkoutRoute || '/plans');
+        this.billing.subscription = data.subscription;
+        this.billing.checkoutRoute = data?.checkoutRoute ?? '/plans';
 
         if (data.subscription.status === 'active' && this.config.hostSettings?.forceUpgrade) {
             // config might not be updated after a subscription has been set to active.
@@ -126,7 +136,7 @@ export default class GhBillingIframe extends Component {
         ) {
             // The action param will be picked up on a transition from the router and can
             // then send the destination route as a message to the BMA, which then handles the redirect.
-            const checkoutAction = this.billing.get('billingRouteRoot') + '?action=checkout';
+            const checkoutAction = this.billing.billingRouteRoot + '?action=checkout';
 
             this.notifications.showAlert(htmlSafe(`Your audience has grown! To continue publishing, the site owner must confirm pricing for this number of members <a href="${checkoutAction}">here</a>`), {type: 'warn', key: 'billing.exceeded'});
         } else {
diff --git a/ghost/admin/app/routes/pro.js b/ghost/admin/app/routes/pro.js
index 20af600d7a..3b61b6f39e 100644
--- a/ghost/admin/app/routes/pro.js
+++ b/ghost/admin/app/routes/pro.js
@@ -21,12 +21,12 @@ export default class ProRoute extends AuthenticatedRoute {
             return this.transitionTo('home');
         }
 
-        this.billing.set('previousTransition', transition);
+        this.billing.previousTransition = transition;
     }
 
     model(params) {
         if (params.action) {
-            this.billing.set('action', params.action);
+            this.billing.action = params.action;
         }
 
         this.billing.toggleProWindow(true);
diff --git a/ghost/admin/app/services/billing.js b/ghost/admin/app/services/billing.js
index 09358150e2..a14ef0c6c7 100644
--- a/ghost/admin/app/services/billing.js
+++ b/ghost/admin/app/services/billing.js
@@ -1,8 +1,7 @@
 import Service, {inject as service} from '@ember/service';
-import classic from 'ember-classic-decorator';
 import {inject} from 'ghost-admin/decorators/inject';
+import {tracked} from '@glimmer/tracking';
 
-@classic
 export default class BillingService extends Service {
     @service ghostPaths;
     @service router;
@@ -11,14 +10,15 @@ export default class BillingService extends Service {
     @inject config;
 
     billingRouteRoot = '#/pro';
-    billingWindowOpen = false;
-    subscription = null;
-    previousRoute = null;
-    action = null;
-    ownerUser = null;
 
-    init() {
-        super.init(...arguments);
+    @tracked billingWindowOpen = false;
+    @tracked subscription = null;
+    @tracked previousRoute = null;
+    @tracked action = null;
+    @tracked ownerUser = null;
+
+    constructor() {
+        super(...arguments);
 
         if (this.config.hostSettings?.billing?.url) {
             window.addEventListener('message', (event) => {
@@ -70,7 +70,7 @@ export default class BillingService extends Service {
                 await this.store.findAll('user', {reload: true});
                 user = this.store.peekAll('user').findBy('isOwnerOnly', true);
             }
-            this.set('ownerUser', user);
+            this.ownerUser = user;
         }
         return this.ownerUser;
     }
@@ -88,7 +88,7 @@ export default class BillingService extends Service {
                 }, '*');
             }
 
-            this.set('action', null);
+            this.action = null;
         }
     }
 
@@ -103,7 +103,7 @@ export default class BillingService extends Service {
 
         this.sendRouteUpdate();
 
-        this.set('billingWindowOpen', value);
+        this.billingWindowOpen = value;
     }
 
     // Controls navigation to billing window modal which is triggered from the application UI.
@@ -119,7 +119,7 @@ export default class BillingService extends Service {
             return;
         }
 
-        this.set('previousRoute', currentRoute);
+        this.previousRoute = currentRoute;
 
         // Ensures correct "getIframeURL" calculation when syncing iframe location
         // in toggleProWindow