diff --git a/setup.cfg b/setup.cfg
index 08cb660..41fe59f 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -37,6 +37,7 @@ install_requires =
     click>=8.1.7
     appdirs>=1.4.4
     lzstring>=1.0.4
+    typing-extensions>=4.0.1
 tests_require =
     pytest>=3
 zip_safe = False