diff --git a/environment.yml b/environment.yml
index 5bb7d36..414a22d 100644
--- a/environment.yml
+++ b/environment.yml
@@ -4,7 +4,7 @@ dependencies:
 - ase =3.26.0
 - assyst =0.9.0
 - atomistics =0.3.2
-- black =25.1.0
+- black =25.9.0
 - calphy =1.4.3
 - conda =25.7.0
 - conda-smithy =3.52.2
diff --git a/requirements.txt b/requirements.txt
index c77f802..c798edb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 ase==3.26.0
 assyst==0.9.0
 atomistics==0.3.2
-black==25.1.0
+black==25.9.0
 calphy==1.4.3
 coverage==7.11.0
 custodian==2025.10.11