diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 78e177d1f752f607e85538e90b39a48ac88d9b37..29a38675d7258a88449d6c4f15d7f761c2eb9193 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,4 +1,4 @@
-Changes in Release 2.x.c
+Changes in Release 2.3.1
 --------------------------------------------------------------------------------
 
  * Simplify Dockerfile - remove MSMS
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c118d3d0a100c940124a48699f21918d43dc815a..5f81621413811bd35930ff6507a3ddfd39e9e359 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,7 +15,7 @@ project(OpenStructure CXX C)
 set (CMAKE_EXPORT_COMPILE_COMMANDS 1)
 set (OST_VERSION_MAJOR 2)
 set (OST_VERSION_MINOR 3)
-set (OST_VERSION_PATCH 0)
+set (OST_VERSION_PATCH 1)
 set (OST_VERSION_STRING ${OST_VERSION_MAJOR}.${OST_VERSION_MINOR}.${OST_VERSION_PATCH} )
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${PROJECT_SOURCE_DIR}/cmake_support)
 include(OST)
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 93ba3a0c638ff7bacaa2d9ae0905cdd89e5b4207..4a1a9bd26ead4670ec8ab8791ed0648c70b23971 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -2,7 +2,7 @@ FROM ubuntu:20.04
 
 # ARGUMENTS
 ###########
-ARG OPENSTRUCTURE_VERSION="2.3.0"
+ARG OPENSTRUCTURE_VERSION="2.3.1"
 ARG SRC_FOLDER="/usr/local/src"
 ARG CPUS_FOR_MAKE=2
 ARG OPENMM_VERSION="7.1.1"
diff --git a/singularity/Singularity b/singularity/Singularity
index dd26e2a39ff55ef5417c5f215ffc0bdcc5775a69..09f83f356b95ceeee34cf0ebbf34d4e38660cc4d 100644
--- a/singularity/Singularity
+++ b/singularity/Singularity
@@ -1,5 +1,5 @@
 BootStrap: docker
-From: registry.scicore.unibas.ch/schwede/openstructure:2.3.0-focal
+From: registry.scicore.unibas.ch/schwede/openstructure:2.3.1-focal
 %post
 ##############################################################################
 # POST