diff --git a/Example49/yarn.lock b/Example49/yarn.lock
index 0c823ae..ef4745f 100644
--- a/Example49/yarn.lock
+++ b/Example49/yarn.lock
@@ -53,8 +53,8 @@ acorn-globals@^4.1.0:
     acorn "^5.0.0"
 
 acorn@^5.0.0, acorn@^5.5.3:
-  version "5.7.1"
-  resolved "https://registry.npmjs.org/acorn/-/acorn-5.7.1.tgz#f095829297706a7c9776958c0afc8930a9b9d9d8"
+  version "5.7.4"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.7.4.tgz#3e8d8a9947d0599a1796d10225d7432f4a4acf5e"
 
 ajv@^5.1.0:
   version "5.5.2"