diff --git a/requirements.txt b/requirements.txt
index 6e4df37..8955910 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,12 +1,12 @@
-certifi==2019.3.9
-babel==2.7.0
-flask-babel==0.12.2
-flask==1.0.2
-idna==2.8
-jinja2==2.10.1
-lxml==4.3.3
-pygments==2.1.3
-pyopenssl==19.0.0
-python-dateutil==2.8.0
-pyyaml==5.1
-requests[socks]==2.22.0
+certifi>2019.3.9
+babel>2.7.0<3
+flask-babel>0.12.2<0.13
+flask>1.0.2<2
+idna>2.8<3
+jinja2>2.10.1<3
+lxml>4.3.3<4
+pygments>2.1.3<3
+pyopenssl>19.0.0<20
+python-dateutil>2.8.0<3
+pyyaml>5.1<6
+requests[socks]>2.22.0<3