diff --git a/README.rst b/README.rst
index 0fac0d0..d48e019 100644
--- a/README.rst
+++ b/README.rst
@@ -51,7 +51,7 @@ Citation
 If you use this library and want to cite it, please cite it as:
 
 Mika Pflüger, Daniel Huppmann & Johannes Gütschow. (2023-07-18).
-pik-primap/unfccc_di_api: Version 4.0.0.
+pik-primap/unfccc_di_api: Version 4.0.1.
 Zenodo. https://doi.org/10.5281/zenodo.8160056
 
 Data package
diff --git a/setup.cfg b/setup.cfg
index 5cf89c6..c4f47b2 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = unfccc_di_api
-version = 4.0.0
+version = 4.0.1
 author = Mika Pflüger
 author_email = mika.pflueger@pik-potsdam.de
 description = Python wrapper around the Flexible Query API of the UNFCCC.
diff --git a/tbump.toml b/tbump.toml
index 99ca316..4273b1c 100644
--- a/tbump.toml
+++ b/tbump.toml
@@ -2,7 +2,7 @@
 github_url = "https://github.com/pik-primap/unfccc_di_api/"
 
 [version]
-current = "4.0.0"
+current = "4.0.1"
 
 # Example of a semver regexp.
 # Make sure this matches current_version before
diff --git a/unfccc_di_api/__init__.py b/unfccc_di_api/__init__.py
index c213925..e50c3a9 100644
--- a/unfccc_di_api/__init__.py
+++ b/unfccc_di_api/__init__.py
@@ -10,7 +10,7 @@
 
 __author__ = """Mika Pflüger"""
 __email__ = "mika.pflueger@pik-potsdam.de"
-__version__ = "4.0.0"
+__version__ = "4.0.1"
 
 from .unfccc_di_api import (
     NoDataError,