diff --git a/.ci_support/environment.yml b/.ci_support/environment.yml
index 48e0ee22c..b390e02f2 100644
--- a/.ci_support/environment.yml
+++ b/.ci_support/environment.yml
@@ -10,7 +10,7 @@ dependencies:
 - numpy =1.26.3
 - phonopy =2.21.0
 - plotly =5.18.0
-- pymatgen =2023.12.18
+- pymatgen =2024.1.27
 - pyscal =2.10.18
 - pyxtal =0.6.1
 - scikit-learn =1.4.0
diff --git a/pyproject.toml b/pyproject.toml
index fbb53c392..69f594f77 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,7 +38,7 @@ Repository = "https://github.com/pyiron/structuretoolkit"
 [project.optional-dependencies]
 grainboundary = [
     "aimsgb==1.1.0",
-    "pymatgen==2023.12.18",
+    "pymatgen==2024.1.27",
 ]
 pyscal = ["pyscal2==2.10.18"]
 nglview = ["nglview==3.1.1"]
@@ -48,7 +48,7 @@ clusters = ["scikit-learn==1.4.0"]
 symmetry = ["spglib==2.2.0"]
 surface = [
     "spglib==2.2.0",
-    "pymatgen==2023.12.18",
+    "pymatgen==2024.1.27",
 ]
 phonopy = [
     "phonopy==2.21.0",
diff --git a/structuretoolkit/analyse/strain.py b/structuretoolkit/analyse/strain.py
index 3632c9dda..f9ebb6aaa 100644
--- a/structuretoolkit/analyse/strain.py
+++ b/structuretoolkit/analyse/strain.py
@@ -6,7 +6,6 @@
 
 
 class Strain:
-
     """
     Calculate local strain of each atom following the Lagrangian strain tensor:
 
diff --git a/structuretoolkit/analyse/symmetry.py b/structuretoolkit/analyse/symmetry.py
index bebeeae37..2da660fee 100644
--- a/structuretoolkit/analyse/symmetry.py
+++ b/structuretoolkit/analyse/symmetry.py
@@ -24,7 +24,6 @@
 
 
 class Symmetry(dict):
-
     """
 
     Return a class for operations related to box symmetries. Main attributes: