diff --git a/packages/frontend/src/boot/main-boot.ts b/packages/frontend/src/boot/main-boot.ts
index ae4e0445db..dd1ec2ff9d 100644
--- a/packages/frontend/src/boot/main-boot.ts
+++ b/packages/frontend/src/boot/main-boot.ts
@@ -30,6 +30,7 @@ import { launchPlugins } from '@/plugin.js';
 import { updateCurrentAccountPartial } from '@/accounts.js';
 import { signout } from '@/signout.js';
 import { migrateOldSettings } from '@/pref-migrate.js';
+import { miRegistoryItem } from '@/registry-item.js';
 
 export async function mainBoot() {
 	const { isClientUpdated, lastVersion } = await common(async () => {
@@ -288,6 +289,8 @@ export async function mainBoot() {
 		//	}
 		//}
 		//miLocalStorage.setItem('lastUsed', Date.now().toString());
+		const channelLastReadedAt = await miRegistoryItem.get('channelsLastReadedAt');
+		miLocalStorage.setItemAsJson('channelsLastReadedAt', channelLastReadedAt);
 
 		const latestDonationInfoShownAt = miLocalStorage.getItem('latestDonationInfoShownAt');
 		const neverShowDonationInfo = miLocalStorage.getItem('neverShowDonationInfo');
diff --git a/packages/frontend/src/components/MkChannelPreview.vue b/packages/frontend/src/components/MkChannelPreview.vue
index f79989d882..c6f5d08299 100644
--- a/packages/frontend/src/components/MkChannelPreview.vue
+++ b/packages/frontend/src/components/MkChannelPreview.vue
@@ -56,7 +56,7 @@ const props = defineProps<{
 }>();
 
 const getLastReadedAt = (): number | null => {
-	return miLocalStorage.getItemAsJson(`channelLastReadedAt:${props.channel.id}`) ?? null;
+	return miLocalStorage.getItemAsJson('channelsLastReadedAt')[props.channel.id] ?? null;
 };
 
 const lastReadedAt = ref(getLastReadedAt());
diff --git a/packages/frontend/src/local-storage.ts b/packages/frontend/src/local-storage.ts
index 78fba9f7b4..17b359479f 100644
--- a/packages/frontend/src/local-storage.ts
+++ b/packages/frontend/src/local-storage.ts
@@ -39,7 +39,8 @@ export type Keys = (
 	`aiscript:${string}` |
 	'lastEmojisFetchedAt' | // DEPRECATED, stored in indexeddb (13.9.0~)
 	'emojis' | // DEPRECATED, stored in indexeddb (13.9.0~);
-	`channelLastReadedAt:${string}` |
+	`channelLastReadedAt:${string}` | // DEPRECATED, stored channelsLastReadedAt and registry
+	'channelsLastReadedAt' |
 	`idbfallback::${string}`
 );
 
diff --git a/packages/frontend/src/pages/channel.vue b/packages/frontend/src/pages/channel.vue
index 6eb390f743..000b8a3bcf 100644
--- a/packages/frontend/src/pages/channel.vue
+++ b/packages/frontend/src/pages/channel.vue
@@ -97,6 +97,7 @@ import { copyToClipboard } from '@/utility/copy-to-clipboard.js';
 import { notesSearchAvailable } from '@/utility/check-permissions.js';
 import { miLocalStorage } from '@/local-storage.js';
 import { useRouter } from '@/router.js';
+import { miRegistoryItem } from '@/registry-item';
 
 const router = useRouter();
 
@@ -131,21 +132,35 @@ watch(() => props.channelId, async () => {
 	channel.value = await misskeyApi('channels/show', {
 		channelId: props.channelId,
 	});
+	if (!channel.value) return;
 	favorited.value = channel.value.isFavorited ?? false;
 	if (favorited.value || channel.value.isFollowing) {
 		tab.value = 'timeline';
 	}
 
 	if ((favorited.value || channel.value.isFollowing) && channel.value.lastNotedAt) {
-		const lastReadedAt: number = miLocalStorage.getItemAsJson(`channelLastReadedAt:${channel.value.id}`) ?? 0;
+		const lastReadedAt = miLocalStorage.getItemAsJson('channelsLastReadedAt')[channel.value.id] ?? undefined;
 		const lastNotedAt = Date.parse(channel.value.lastNotedAt);
 
+		if (!lastReadedAt) {
+			saveLastReadedAt();
+			return;
+		}
+
 		if (lastNotedAt > lastReadedAt) {
-			miLocalStorage.setItemAsJson(`channelLastReadedAt:${channel.value.id}`, lastNotedAt);
+			saveLastReadedAt();
 		}
 	}
 }, { immediate: true });
 
+async function saveLastReadedAt() {
+	if (!channel.value) return;
+	const tmp = await miRegistoryItem.get('channelsLastReadedAt');
+	tmp[channel.value.id] = Date.now();
+	await miRegistoryItem.set('channelsLastReadedAt', tmp);
+	miLocalStorage.setItemAsJson('channelsLastReadedAt', tmp);
+}
+
 function edit() {
 	router.push(`/channels/${channel.value?.id}/edit`);
 }
diff --git a/packages/frontend/src/pages/timeline.vue b/packages/frontend/src/pages/timeline.vue
index b783f7ee0b..aaeab902f6 100644
--- a/packages/frontend/src/pages/timeline.vue
+++ b/packages/frontend/src/pages/timeline.vue
@@ -148,7 +148,7 @@ async function chooseChannel(ev: MouseEvent): Promise<void> {
 	const channels = await favoritedChannelsCache.fetch();
 	const items: MenuItem[] = [
 		...channels.map(channel => {
-			const lastReadedAt = miLocalStorage.getItemAsJson(`channelLastReadedAt:${channel.id}`) ?? null;
+			const lastReadedAt = miLocalStorage.getItemAsJson('channelsLastReadedAt')[channel.id] ?? null;
 			const hasUnreadNote = (lastReadedAt && channel.lastNotedAt) ? Date.parse(channel.lastNotedAt) > lastReadedAt : !!(!lastReadedAt && channel.lastNotedAt);
 
 			return {
diff --git a/packages/frontend/src/registry-item.ts b/packages/frontend/src/registry-item.ts
new file mode 100644
index 0000000000..9b1a8ff546
--- /dev/null
+++ b/packages/frontend/src/registry-item.ts
@@ -0,0 +1,25 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { misskeyApi } from '@/utility/misskey-api.js';
+
+export type Keys =
+	'channelsLastReadedAt' | // DEPRECATED, stored registory(2025.1.xxx)
+	'somethingElse';
+
+export const miRegistoryItem = {
+	async get(key: Keys) {
+		try {
+			return JSON.parse(await misskeyApi('i/registry/get', { scope: ['client'], key }));
+		} catch (err) {
+			if (err.code === 'NO_SUCH_KEY') return {};
+			throw err;
+		}
+	},
+	async set(key: Keys, payload) {
+		await misskeyApi('i/registry/set', { scope: ['client'], key, value: JSON.stringify(payload) });
+	},
+};
+