diff --git a/package.json b/package.json
index 32e020b..e8158d8 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "@microsoft/api-extractor": "7.13.2",
     "@types/chai": "4.2.15",
     "@types/chai-as-promised": "7.1.3",
-    "@types/js-yaml": "3.12.6",
+    "@types/js-yaml": "4.0.0",
     "@types/lodash": "4.14.168",
     "@types/mocha": "8.2.2",
     "@types/sinon-chai": "3.2.5",
@@ -36,7 +36,7 @@
     "eslint-plugin-no-null": "1.0.2",
     "eslint-plugin-sonarjs": "0.6.0",
     "esm": "3.2.25",
-    "js-yaml": "3.14.1",
+    "js-yaml": "4.0.0",
     "mocha": "8.3.2",
     "noicejs": "3.1.0",
     "nyc": "15.1.0",
diff --git a/src/schema.ts b/src/schema.ts
index 5f04e02..533eca2 100644
--- a/src/schema.ts
+++ b/src/schema.ts
@@ -1,4 +1,4 @@
-import { DEFAULT_SAFE_SCHEMA, Schema } from 'js-yaml';
+import { DEFAULT_SCHEMA } from 'js-yaml';
 
 import { envType } from './type/Env';
 import { createInclude, IncludeOptions } from './type/Include';
@@ -16,7 +16,7 @@ export interface SchemaOptions {
  */
 export function createSchema(options: SchemaOptions) {
   const includeType = createInclude(options.include);
-  const schema = Schema.create([DEFAULT_SAFE_SCHEMA], [
+  const schema = DEFAULT_SCHEMA.extend([
     envType,
     includeType,
     regexpType,
diff --git a/src/type/Include.ts b/src/type/Include.ts
index 738fcec..33fb21b 100644
--- a/src/type/Include.ts
+++ b/src/type/Include.ts
@@ -1,5 +1,5 @@
 import { InvalidArgumentError, NotFoundError } from '@apextoaster/js-utils';
-import { safeLoad, Schema, Type as YamlType } from 'js-yaml';
+import { load, Schema, Type as YamlType } from 'js-yaml';
 
 export type ReaderEncoding = 'ascii' | 'utf-8';
 export interface ReaderOptions {
@@ -40,7 +40,7 @@ export function createInclude(options: IncludeOptions) {
     construct(path: string): unknown {
       try {
         const abs = options.resolve(path);
-        return safeLoad(options.read(abs, {
+        return load(options.read(abs, {
           encoding: 'utf-8',
         }), {
           schema: options.schema,
diff --git a/test/type/TestInclude.ts b/test/type/TestInclude.ts
index 61c4d29..33478df 100644
--- a/test/type/TestInclude.ts
+++ b/test/type/TestInclude.ts
@@ -1,6 +1,6 @@
 import { InvalidArgumentError, NotFoundError } from '@apextoaster/js-utils';
 import { expect } from 'chai';
-import { DEFAULT_SAFE_SCHEMA } from 'js-yaml';
+import { DEFAULT_SCHEMA } from 'js-yaml';
 import { join } from 'path';
 
 import { createInclude, IncludeOptions } from '../../src/type/Include';
@@ -12,7 +12,7 @@ const TEST_OPTIONS: IncludeOptions = {
   join: (...path) => path.join('/'),
   read: () => 'test',
   resolve: (path: string) => path,
-  schema: DEFAULT_SAFE_SCHEMA,
+  schema: DEFAULT_SCHEMA,
 };
 
 describe('include config type', async () => {
diff --git a/yarn.lock b/yarn.lock
index c83f552..7f8dc81 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -386,10 +386,10 @@
   resolved "https://artifacts.apextoaster.com/repository/group-npm/@types/estree/-/estree-0.0.39.tgz#e177e699ee1b8c22d23174caaa7422644389509f"
   integrity sha512-EYNwp3bU+98cpU4lAWYYL7Zz+2gryWH1qbdDTidVd6hkiR6weksdbMadyXKXNPEkQFhXM+hVO9ZygomHXp+AIw==
 
-"@types/js-yaml@3.12.6":
-  version "3.12.6"
-  resolved "https://artifacts.apextoaster.com/repository/group-npm/@types/js-yaml/-/js-yaml-3.12.6.tgz#7f10c926aa41e189a2755c4c7fcf8e4573bd7ac1"
-  integrity sha512-cK4XqrLvP17X6c0C8n4iTbT59EixqyXL3Fk8/Rsk4dF3oX4dg70gYUXrXVUUHpnsGMPNlTQMqf+TVmNPX6FmSQ==
+"@types/js-yaml@4.0.0":
+  version "4.0.0"
+  resolved "https://artifacts.apextoaster.com/repository/group-npm/@types/js-yaml/-/js-yaml-4.0.0.tgz#d1a11688112091f2c711674df3a65ea2f47b5dfb"
+  integrity sha512-4vlpCM5KPCL5CfGmTbpjwVKbISRYhduEJvvUWsH5EB7QInhEj94XPZ3ts/9FPiLZFqYO0xoW4ZL8z2AabTGgJA==
 
 "@types/json-schema@^7.0.3":
   version "7.0.3"
@@ -2583,14 +2583,6 @@ js-tokens@^4.0.0:
   resolved "https://artifacts.apextoaster.com/repository/group-npm/js-tokens/-/js-tokens-4.0.0.tgz#19203fb59991df98e3a287050d4647cdeaf32499"
   integrity sha512-RdJUflcE3cUzKiMqQgsCu06FPu9UdIJO0beYbPhHN4k6apgJtifcoCtT9bcxOpYBtpD2kCM6Sbzg4CausW/PKQ==
 
-js-yaml@3.14.1:
-  version "3.14.1"
-  resolved "https://artifacts.apextoaster.com/repository/group-npm/js-yaml/-/js-yaml-3.14.1.tgz#dae812fdb3825fa306609a8717383c50c36a0537"
-  integrity sha512-okMH7OXXJ7YrN9Ok3/SXrnu4iX9yOk+25nqX4imS2npuvTYDmo/QEZoqwZkYaIDk3jVvBOTOIEgEhaLOynBS9g==
-  dependencies:
-    argparse "^1.0.7"
-    esprima "^4.0.0"
-
 js-yaml@4.0.0:
   version "4.0.0"
   resolved "https://artifacts.apextoaster.com/repository/group-npm/js-yaml/-/js-yaml-4.0.0.tgz#f426bc0ff4b4051926cd588c71113183409a121f"