diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd5165cee9793f434bbc6a1c703ae2692fcb5571..7f2d509a28c93722ffa1bcdf51391fab2455b086 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,22 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased] ##
+
+### Added ###
+
+### Changed ###
+
+### Deprecated ###
+
+### Removed ###
+
+### Fixed ###
+
+### Security ###
+
+### Documentation ###
+
 ## [0.12.0] - 2023-06-02 ##
 
 ### Added ###
diff --git a/setup.py b/setup.py
index 4bed95b727e5d4e0b39d64e4d3809bbdd620628c..8fdf3b1c63322ec48af398d1dcb1c4028355d473 100755
--- a/setup.py
+++ b/setup.py
@@ -45,10 +45,10 @@ from setuptools import find_packages, setup
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ########################################################################
 
-ISRELEASED = True
+ISRELEASED = False
 MAJOR = 0
 MINOR = 12
-MICRO = 0
+MICRO = 1
 # Do not tag as pre-release until this commit
 # https://github.com/pypa/packaging/pull/515
 # has made it into a release. Probably we should wait for pypa/packaging>=21.4
diff --git a/src/doc/conf.py b/src/doc/conf.py
index 7a2cbe4910b48ad714ce6d9eb40a368c2a666f6e..0fa5de575f5424e267cad8ecc193cca8230faa8b 100644
--- a/src/doc/conf.py
+++ b/src/doc/conf.py
@@ -29,10 +29,10 @@ copyright = '2023, IndiScale GmbH'
 author = 'Daniel Hornung'
 
 # The short X.Y version
-version = '0.12.0'
+version = '0.12.1'
 # The full version, including alpha/beta/rc tags
 # release = '0.5.2-rc2'
-release = '0.12.0'
+release = '0.12.1-dev'
 
 
 # -- General configuration ---------------------------------------------------