diff --git a/.node-version b/.node-version
index 7fd023741b..e44a38e080 100644
--- a/.node-version
+++ b/.node-version
@@ -1 +1 @@
-v16.15.0
+v18.12.1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 92e47077de..f1bc0a96fd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ You should also include the user name that made the change.
 ## 12.x.x (unreleased)
 
 ### Changes
+- Node.js 18.x or later is required
 - Elasticsearchのサポートが削除されました
 	- 代わりに今後任意の検索プロバイダを設定できる仕組みを構想しています。その仕組みを使えば今まで通りElasticsearchも利用できます
 - ノートのウォッチ機能が削除されました
diff --git a/Dockerfile b/Dockerfile
index 81dc726375..0151797a7b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM node:16.15.1-bullseye AS builder
+FROM node:18.12.1-bullseye AS builder
 
 ARG NODE_ENV=production
 
@@ -13,7 +13,7 @@ RUN yarn install
 RUN yarn build
 RUN rm -rf .git
 
-FROM node:16.15.1-bullseye-slim AS runner
+FROM node:18.12.1-bullseye-slim AS runner
 
 WORKDIR /misskey
 
diff --git a/packages/backend/src/core/RelayService.ts b/packages/backend/src/core/RelayService.ts
index 5324826ec1..563eeac0f0 100644
--- a/packages/backend/src/core/RelayService.ts
+++ b/packages/backend/src/core/RelayService.ts
@@ -105,9 +105,7 @@ export class RelayService {
 		}));
 		if (relays.length === 0) return;
 	
-		// TODO
-		//const copy = structuredClone(activity);
-		const copy = JSON.parse(JSON.stringify(activity));
+		const copy = structuredClone(activity);
 		if (!copy.to) copy.to = ['https://www.w3.org/ns/activitystreams#Public'];
 	
 		const signed = await this.apRendererService.attachLdSignature(copy, user);
diff --git a/packages/backend/src/core/entities/DriveFileEntityService.ts b/packages/backend/src/core/entities/DriveFileEntityService.ts
index f0ac6518d0..d9430e1497 100644
--- a/packages/backend/src/core/entities/DriveFileEntityService.ts
+++ b/packages/backend/src/core/entities/DriveFileEntityService.ts
@@ -55,9 +55,7 @@ export class DriveFileEntityService {
 
 	public getPublicProperties(file: DriveFile): DriveFile['properties'] {
 		if (file.properties.orientation != null) {
-			// TODO
-			//const properties = structuredClone(file.properties);
-			const properties = JSON.parse(JSON.stringify(file.properties));
+			const properties = structuredClone(file.properties);
 			if (file.properties.orientation >= 5) {
 				[properties.width, properties.height] = [properties.height, properties.width];
 			}
diff --git a/packages/backend/src/server/web/ClientServerService.ts b/packages/backend/src/server/web/ClientServerService.ts
index 30d430775c..44450245a6 100644
--- a/packages/backend/src/server/web/ClientServerService.ts
+++ b/packages/backend/src/server/web/ClientServerService.ts
@@ -86,9 +86,7 @@ export class ClientServerService {
 	}
 
 	private async manifestHandler(ctx: Koa.Context) {
-		// TODO
-		//const res = structuredClone(manifest);
-		const res = JSON.parse(JSON.stringify(manifest));
+		const res = structuredClone(manifest);
 
 		const instance = await this.metaService.fetch(true);