diff --git a/package.json b/package.json
index 7a1afa9..ebde328 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,7 @@
     "nyc": "^14",
     "sinon": "5",
     "ts-node": "^9",
-    "typescript": "3"
+    "typescript": "4"
   },
   "engines": {
     "node": ">=8.0.0"
diff --git a/yarn.lock b/yarn.lock
index be1ea0a..1553db9 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3640,10 +3640,10 @@ typedarray-to-buffer@^3.1.5:
   dependencies:
     is-typedarray "^1.0.0"
 
-typescript@3:
-  version "3.9.7"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.7.tgz#98d600a5ebdc38f40cb277522f12dc800e9e25fa"
-  integrity sha512-BLbiRkiBzAwsjut4x/dsibSTB6yWpwT5qWmC2OfuCg3GgVQCSgMs4vEctYPhsaGtd0AeuuHMkjZ2h2WG8MSzRw==
+typescript@4:
+  version "4.2.4"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.2.4.tgz#8610b59747de028fda898a8aef0e103f156d0961"
+  integrity sha512-V+evlYHZnQkaz8TRBuxTA92yZBPotr5H+WhQ7bD3hZUndx5tGOa1fuCgeSjxAzM1RiN5IzvadIXTVefuuwZCRg==
 
 union-value@^1.0.0:
   version "1.0.1"