diff --git a/pyxtal/crystal.py b/pyxtal/crystal.py
index 7e889794..718467bb 100644
--- a/pyxtal/crystal.py
+++ b/pyxtal/crystal.py
@@ -1549,6 +1549,7 @@ class Lattice():
             'allow_volume_reset': a bool stating whether or not the volume should be reset during
                 each crystal generation attempt
     """
+
     def __init__(self, ltype, volume, PBC=[1,1,1], **kwargs):
         #Set required parameters
         if ltype in ["triclinic", "monoclinic", "orthorhombic", "tetragonal",
diff --git a/requirements.txt b/requirements.txt
index eb2cb937..c9015bbd 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
 numpy>=1.13.3 
-scipy>=1.1.0
+scipy>=1.5.0
 spglib>=1.10.4
 pymatgen>=2020.1.28
diff --git a/setup.py b/setup.py
index 9d0cd76c..59e86bec 100755
--- a/setup.py
+++ b/setup.py
@@ -42,7 +42,7 @@
     ],
     install_requires=[
         'numpy>=1.13.3', 
-        'scipy>=1.1.0', 
+        'scipy>=1.5.0', 
         'spglib>=1.10.4',
         'pymatgen>=2020.1.28'],
     python_requires='>=3.6.1',