diff --git a/example/package.json b/example/package.json
index 7eeb8557..886ab107 100644
--- a/example/package.json
+++ b/example/package.json
@@ -22,6 +22,6 @@
   "devDependencies": {
     "@babel/core": "7.15.0",
     "parcel-bundler": "1.12.5",
-    "typescript": "3.4.5"
+    "typescript": "3.9.10"
   }
 }
diff --git a/package.json b/package.json
index 8d04fc6e..6139c6bc 100644
--- a/package.json
+++ b/package.json
@@ -48,6 +48,6 @@
     "prettier": "1.19.1",
     "renovate-config-nju33": "0.0.1",
     "tslint": "5.20.1",
-    "typescript": "3.4.5"
+    "typescript": "3.9.10"
   }
 }
diff --git a/packages/gsw/package.json b/packages/gsw/package.json
index 731b6436..501cbbf9 100644
--- a/packages/gsw/package.json
+++ b/packages/gsw/package.json
@@ -43,7 +43,7 @@
     "ts-node": "7.0.1",
     "tslint": "5.20.1",
     "typedoc": "0.20.36",
-    "typescript": "3.4.5"
+    "typescript": "3.9.10"
   },
   "keywords": [
     "object"
diff --git a/yarn.lock b/yarn.lock
index 0751d1c3..46e9a605 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -11094,10 +11094,10 @@ typedoc@0.20.36:
     shiki "^0.9.3"
     typedoc-default-themes "^0.12.10"
 
-typescript@3.4.5:
-  version "3.4.5"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.4.5.tgz#2d2618d10bb566572b8d7aad5180d84257d70a99"
-  integrity sha512-YycBxUb49UUhdNMU5aJ7z5Ej2XGmaIBL0x34vZ82fn3hGvD+bgrMrVDpatgz2f7YxUMJxMkbWxJZeAvDxVe7Vw==
+typescript@3.9.10:
+  version "3.9.10"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.10.tgz#70f3910ac7a51ed6bef79da7800690b19bf778b8"
+  integrity sha512-w6fIxVE/H1PkLKcCPsFqKE7Kv7QUwhU8qQY2MueZXWx5cPZdwFupLgKK3vntcK98BtNHZtAF4LA/yl2a7k8R6Q==
 
 uglify-js@^3.1.4:
   version "3.4.9"