diff --git a/requirements.txt b/requirements.txt
index 3821033..8e21c68 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 absl-py~=1.0.0
-attrs~=21.2.0
+attrs~=21.4.0
 dm-tree~=0.1.1
 matplotlib~=3.3.4
 mpmath