diff --git a/requirements.txt b/requirements.txt
index 4168ad2..e140da6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 pyproj==3.1.0
 ## The following requirements were added by pip freeze:
-attrs==21.2.0
+attrs==21.4.0
 certifi==2021.5.30
 cjio==0.6.9
 click==8.0.1