diff --git a/mdxpy/mdx.py b/mdxpy/mdx.py
index 6b42238..200f693 100644
--- a/mdxpy/mdx.py
+++ b/mdxpy/mdx.py
@@ -1254,8 +1254,8 @@ def to_mdx(self, head_columns: int = None, head_rows: int = None, tail_columns:
             self._axis_mdx(
                 position,
                 # default for head, tail is False for axes beyond rows and columns
-                head=head_by_axis_position.get(position, False),
-                tail=tail_by_axis_position.get(position, False),
+                head=head_by_axis_position.get(position, None),
+                tail=tail_by_axis_position.get(position, None),
                 skip_dimension_properties=skip_dimension_properties)
             for position
             in self.axes)
diff --git a/setup.py b/setup.py
index 653b0e8..a515a71 100644
--- a/setup.py
+++ b/setup.py
@@ -4,7 +4,7 @@
 
 setup(
     name="mdxpy",
-    version='1.3',
+    version='1.3.1',
     maintainer='Marius Wirtz',
     maintainer_email='MWirtz@cubewise.com',
     license="MIT-LICENSE",