diff --git a/package.json b/package.json
index 0a1180d..24fe192 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,6 @@
     "tslint-config-ikatyang": "2.5.1",
     "tslint-config-prettier": "1.13.0",
     "tslint-plugin-prettier": "1.3.0",
-    "typescript": "2.8.3"
+    "typescript": "2.9.1"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index bfcda76..6e87d10 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3349,9 +3349,9 @@ type-detect@^4.0.0:
   version "4.0.8"
   resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.8.tgz#7646fb5f18871cfbb7749e69bd39a6388eb7450c"
 
-typescript@2.8.3:
-  version "2.8.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.8.3.tgz#5d817f9b6f31bb871835f4edf0089f21abe6c170"
+typescript@2.9.1:
+  version "2.9.1"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.9.1.tgz#fdb19d2c67a15d11995fd15640e373e09ab09961"
 
 uglify-js@^2.6:
   version "2.8.29"