diff --git a/components/notification/NotificationCard.vue b/components/notification/NotificationCard.vue
index 25a5af95a2..c5c50dac3e 100644
--- a/components/notification/NotificationCard.vue
+++ b/components/notification/NotificationCard.vue
@@ -141,6 +141,13 @@ if (unsupportedEmojiReactionTypes.includes(notification.type) || !supportedNotif
       <div flex p4 items-center>
         <div i-material-symbols:heart-broken-outline-rounded text-xl me-4 color-red />
         <div class="content-rich">
+          <!--
+            @vue-ignore
+            The type inference failed here (`any`) but since notification type is `severed_relationships`,
+            we are sure `typeof notification === SeveredRelationshipsNotification` here.
+            So we can assume the existence of `event` prop.
+            ref. https://docs.joinmastodon.org/entities/Notification/#relationship_severance_event
+          -->
           <RelationshipSeveranceCard :event="notification.event!" />
         </div>
       </div>
diff --git a/components/notification/RelationshipSeveranceCard.vue b/components/notification/RelationshipSeveranceCard.vue
index 806ca4239a..5adc0dc467 100644
--- a/components/notification/RelationshipSeveranceCard.vue
+++ b/components/notification/RelationshipSeveranceCard.vue
@@ -1,6 +1,14 @@
 <script setup lang="ts">
+import type { mastodon } from 'masto'
+
+// TODO: masto.js needs to update those two props modified in Mastodon v4.3+
+// ref. RelationshipSeveranceEvent - Mastodon documentation
+// - https://docs.joinmastodon.org/entities/RelationshipSeveranceEvent/
 const { event } = defineProps<{
-  event: object
+  event: mastodon.v1.RelationshipSeveranceEvent & {
+    followersCount?: number | null
+    followingCount?: number | null
+  }
 }>()
 
 const { t } = useI18n()