diff --git a/pip-sample/requirements.txt b/pip-sample/requirements.txt
index 680d08166..76b743a27 100644
--- a/pip-sample/requirements.txt
+++ b/pip-sample/requirements.txt
@@ -28,7 +28,7 @@ matplotlib==2.2.2
 mistune==0.8.3
 nbconvert==5.4.0
 nbformat==4.4.0
-nltk==3.3
+nltk==3.9.3
 notebook==5.7.0
 numpy==1.15.3
 oauthlib==2.1.0
@@ -55,7 +55,7 @@ simplegeneric==0.8.1
 six==1.11.0
 terminado==0.8.1
 testpath==0.4.1
-tornado==5.1.1
+tornado==6.5.5
 traitlets==4.3.2
 tweepy==3.6.0
 urllib3==1.23