diff --git a/src/pymap3d/__init__.py b/src/pymap3d/__init__.py
index 0544080..7541de8 100644
--- a/src/pymap3d/__init__.py
+++ b/src/pymap3d/__init__.py
@@ -29,7 +29,7 @@
 * Fortran: [Maptran3D](https://github.com/geospace-code/maptran3d)
 """
 
-__version__ = "3.1.0"
+__version__ = "3.1.1"
 
 from .aer import aer2ecef, aer2geodetic, ecef2aer, geodetic2aer
 from .ecef import (