diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ea4acaa..c5b0bc9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -5,20 +5,20 @@ jobs:
   NodeJS:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
-      - uses: actions/setup-node@v1
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
-          node-version: 12.x
+          node-version: 16.x
       - run: npm install
       - run: npm run compile
       - run: npm run test:node
   Browser:
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v1
-      - uses: actions/setup-node@v1
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
         with:
-          node-version: 12.x
+          node-version: 16.x
       - run: npm install --force
       - run: npm run compile
       - run: npm run bundle
diff --git a/package.json b/package.json
index 84e048d..96bdce0 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,7 @@
     "email": "samchon.github@gmail.com",
     "url": "https://github.com/samchon"
   },
-  "version": "0.8.7",
+  "version": "0.8.8",
   "main": "index.js",
   "typings": "index.d.ts",
   "scripts": {
@@ -28,8 +28,8 @@
   "dependencies": {
     "import2": "^1.0.0",
     "serialize-error": "^4.1.0",
-    "tstl": "^2.5.3",
-    "uuid": "^3.4.0",
+    "tstl": "^2.5.13",
+    "uuid": "^9.0.0",
     "ws": "^7.5.3"
   },
   "devDependencies": {
@@ -48,8 +48,8 @@
     "puppeteer": "^10.1.0",
     "source-map-support": "^0.5.19",
     "ts-node": "^10.1.0",
-    "typedoc": "^0.22.10",
-    "typescript": "^4.5.2",
+    "typedoc": "^0.25.0",
+    "typescript": "^5.2.2",
     "whatwg-fetch": "^3.6.2"
   },
   "homepage": "https://tgrid.com",
diff --git a/src/protocols/web/WebConnector.ts b/src/protocols/web/WebConnector.ts
index 4a76be4..2cbbafa 100644
--- a/src/protocols/web/WebConnector.ts
+++ b/src/protocols/web/WebConnector.ts
@@ -125,9 +125,9 @@ export class WebConnector<Header, Provider extends object | null>
             }
         } catch (exp) {
             this.state_ = WebConnector.State.NONE;
-            if (this.socket_!.readyState === WebConnector.State.OPEN) {
-                this.socket_!.onclose = () => {};
-                this.socket_!.close();
+            if (this.socket_ && this.socket_.readyState === WebConnector.State.OPEN) {
+                this.socket_.onclose = () => {};
+                this.socket_.close();
             }
             throw exp;
         }