diff --git a/CHANGELOG.md b/CHANGELOG.md
index d7fc256..85e63e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,4 @@
-# Changelog
+# Redmine Changelog
 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/),
@@ -6,6 +6,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [v4.2.1-2] - 2021-07-30
+### Changed
+- update version of CAS plugin to 1.4.4 #61
+
+### Added
+- Add RAILS_RELATIVE_URL_ROOT environment variable to startup.sh
+
 ## [v4.2.1-1] - 2021-06-28
 ### Changed
 - Upgrade redmine to 4.2.1; #59
diff --git a/Dockerfile b/Dockerfile
index 88bffe9..39cff2c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,14 +2,14 @@
 FROM registry.cloudogu.com/official/base:3.12.4-1
 
 LABEL NAME="official/redmine" \
-   VERSION="4.2.1-1" \
+   VERSION="4.2.1-2" \
    maintainer="robert.auer@cloudogu.com"
 
 # This Dockerfile is based on https://github.com/docker-library/redmine/blob/master/4.0/alpine/Dockerfile
 
 # set environment variables
 ENV REDMINE_VERSION=4.2.1 \
-    CAS_PLUGIN_VERSION=1.3.1 \
+    CAS_PLUGIN_VERSION=1.4.4 \
     ACTIVERECORD_SESSION_STORE_PLUGIN_VERSION=0.1.0 \
     EXTENDED_REST_API_PLUGIN_VERSION=1.0.0 \
     RUBYCASVERSION=2.3.15 \
@@ -19,7 +19,7 @@ ENV REDMINE_VERSION=4.2.1 \
     SERVICE_TAGS=webapp \
     RAILS_ENV=production \
     REDMINE_TARGZ_SHA256=ad4109c3425f1cfe4c8961f6ae6494c76e20d81ed946caa1e297d9eda13b41b4 \
-    CAS_PLUGIN_TARGZ_SHA256=8f6c9273bded0e8f689c325d44acc12e48df33176f4b172a59ac03077e742170 \
+    CAS_PLUGIN_TARGZ_SHA256=36efac1229af0e2830a9c6a45eff1c1a3e83afbd2aded0bf4c85cb17d5d93a25 \
     EXTENDED_REST_API_TARGZ_SHA256=eedd4c8a9a707a8ac0f499d79c686ed8faf8bc603118a54c18e4829faaeee320 \
     ACTIVERECORD_TARGZ_SHA256=a5d3a5ac6c5329212621bab128a2f94b0ad6bb59084f3cc714786a297bcdc7ee \
     RUBYCAS_TARGZ_SHA256=9ca9b2e020c4f12c3c7e87565b9aa19dda130912138d80ad6775e5bdc2d4ca66 \
@@ -98,7 +98,7 @@ RUN set -eux -o pipefail \
  && mkdir "${WORKDIR}/plugins/redmine_cas" \
  && wget -O v${CAS_PLUGIN_VERSION}.tar.gz "https://github.com/cloudogu/redmine_cas/archive/v${CAS_PLUGIN_VERSION}.tar.gz" \
  && echo "${CAS_PLUGIN_TARGZ_SHA256} *v${CAS_PLUGIN_VERSION}.tar.gz" | sha256sum -c - \
- && tar xfz v${CAS_PLUGIN_VERSION}.tar.gz --strip-components=1 -C "${WORKDIR}/plugins/redmine_cas" \
+ && tar -C "${WORKDIR}/plugins/redmine_cas" --strip-components=2 -zxf "v${CAS_PLUGIN_VERSION}.tar.gz" "redmine_cas-${CAS_PLUGIN_VERSION}/src" \
  && rm v${CAS_PLUGIN_VERSION}.tar.gz \
  # install Cloudogu theme
  && mkdir -p "${WORKDIR}/public/themes/Cloudogu" \
diff --git a/dogu.json b/dogu.json
index 59e8ed9..af2be24 100644
--- a/dogu.json
+++ b/dogu.json
@@ -1,6 +1,6 @@
 {
   "Name": "official/redmine",
-  "Version": "4.2.1-1",
+  "Version": "4.2.1-2",
   "DisplayName": "Redmine",
   "Description": "Redmine is a flexible project management web application",
   "Category": "Development Apps",
diff --git a/resources/startup.sh b/resources/startup.sh
index 4022fbb..ccdfd0a 100755
--- a/resources/startup.sh
+++ b/resources/startup.sh
@@ -243,4 +243,4 @@ doguctl state "ready"
 
 # Start redmine
 echo "Starting redmine..."
-exec su - redmine -c "FQDN=${FQDN} ADMIN_GROUP=${ADMIN_GROUP} puma -e ${RAILS_ENV} -p 3000"
+exec su - redmine -c "FQDN=${FQDN} ADMIN_GROUP=${ADMIN_GROUP} RAILS_RELATIVE_URL_ROOT=${RAILS_RELATIVE_URL_ROOT} puma -e ${RAILS_ENV} -p 3000"