diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 60bd29ba..db1f1aa2 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 0.3.1
+current_version = 0.4.0
 commit = True
 tag = True
 
diff --git a/README.rst b/README.rst
index 0290a1f0..b46259cd 100644
--- a/README.rst
+++ b/README.rst
@@ -32,9 +32,9 @@ Overview
     :alt: PyPI Package latest release
     :target: https://pypi.python.org/pypi/dtscalibration
 
-.. |commits-since| image:: https://img.shields.io/github/commits-since/bdestombe/python-dts-calibration/v0.3.1.svg
+.. |commits-since| image:: https://img.shields.io/github/commits-since/bdestombe/python-dts-calibration/v0.4.0.svg
     :alt: Commits since latest release
-    :target: https://github.com/bdestombe/python-dts-calibration/compare/v0.3.1...master
+    :target: https://github.com/bdestombe/python-dts-calibration/compare/v0.4.0...master
 
 .. |wheel| image:: https://img.shields.io/pypi/wheel/dtscalibration.svg
     :alt: PyPI Wheel
diff --git a/docs/conf.py b/docs/conf.py
index a045c20b..d30160c7 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -35,7 +35,7 @@
 year = '2018'
 author = 'Bas des Tombe'
 copyright = '{0}, {1}'.format(year, author)
-version = release = '0.3.1'
+version = release = '0.4.0'
 
 pygments_style = 'trac'
 templates_path = ['.']
diff --git a/setup.py b/setup.py
index 189bd001..bb2e70ee 100644
--- a/setup.py
+++ b/setup.py
@@ -24,7 +24,7 @@ def read(*names, **kwargs):
 
 setup(
     name='dtscalibration',
-    version='0.3.1',
+    version='0.4.0',
     license='BSD 3-Clause License',
     description='A Python package to load raw DTS files, perform a calibration, and plot the '
                 'result',
diff --git a/src/dtscalibration/__init__.py b/src/dtscalibration/__init__.py
index b66347ac..4a3f8bb4 100644
--- a/src/dtscalibration/__init__.py
+++ b/src/dtscalibration/__init__.py
@@ -3,5 +3,5 @@
 from .datastore import open_datastore
 from .datastore import read_xml_dir
 
-__version__ = '0.3.1'
+__version__ = '0.4.0'
 __all__ = ["DataStore", "open_datastore", "read_xml_dir"]