diff --git a/requirements.txt b/requirements.txt
index ea5d2b48..301ee47f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -16,7 +16,7 @@ pytz==2012j
 icalendar==3.4
 python-dateutil==2.1
 flask-bcrypt==0.5.2
-numpy==1.10.1
+numpy==1.21.0
 py4j==0.9
 
 # Useful for local development, e.g. by tools/devshell.py