diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2419b32ffa48bdc9f0d1c93319348dea70cd744c..5b6446abe1cd8092bb03d143f902427931350f47 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,22 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased] ##
+
+### Added ###
+
+### Changed ###
+
+### Deprecated ###
+
+### Removed ###
+
+### Fixed ###
+
+### Security ###
+
+### Documentation ###
+
 ## [0.9.0] - 2023-11-27 ##
 
 ### Added ###
diff --git a/setup.py b/setup.py
index 50cb59467a5162663d31a23e4cfd2159a611bf9c..a35bcad4979ea272c38563cfe89562d814ee5901 100755
--- a/setup.py
+++ b/setup.py
@@ -47,9 +47,9 @@ from setuptools import find_packages, setup
 
 MAJOR = 0
 MINOR = 9
-MICRO = 0
+MICRO = 1
 PRE = ""  # e.g. rc0, alpha.1, 0.beta-23
-ISRELEASED = True
+ISRELEASED = False
 
 if PRE:
     VERSION = "{}.{}.{}-{}".format(MAJOR, MINOR, MICRO, PRE)
diff --git a/src/doc/conf.py b/src/doc/conf.py
index 60630cf6c2c00aae2c9a48a328613e247e0a4015..590feca405444032b0cdaa5fefc3aff09538bff0 100644
--- a/src/doc/conf.py
+++ b/src/doc/conf.py
@@ -27,9 +27,9 @@ copyright = '2023, IndiScale GmbH'
 author = 'Daniel Hornung'
 
 # The short X.Y version
-version = '0.9.0'
+version = '0.9.1'
 # The full version, including alpha/beta/rc tags
-release = '0.9.0'
+release = '0.9.1-dev'
 
 
 # -- General configuration ---------------------------------------------------