diff --git a/session-20170509/package.json b/session-20170509/package.json
index cc2e596..2e5e11d 100644
--- a/session-20170509/package.json
+++ b/session-20170509/package.json
@@ -5,7 +5,7 @@
   "license": "MIT",
   "dependencies": {
     "@types/lodash": "^4.14.62",
-    "lodash": "^4.14.62"
+    "lodash": "^4.17.21"
   },
   "devDependencies": {
     "@types/chai": "^3.5.0",
diff --git a/session-20170509/yarn.lock b/session-20170509/yarn.lock
index c651bee..ec82f29 100644
--- a/session-20170509/yarn.lock
+++ b/session-20170509/yarn.lock
@@ -192,9 +192,9 @@ lodash.keys@^3.0.0:
     lodash.isarguments "^3.0.0"
     lodash.isarray "^3.0.0"
 
-lodash@^4.14.62:
-  version "4.17.4"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"
+lodash@^4.17.21:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
 
 make-error@^1.1.1:
   version "1.2.3"