diff --git a/docker-compose.yml b/docker-compose.yml
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -56,6 +56,7 @@
       - /var/tmp
     tty: true
     volumes:
+      - ./ext/:/src/:ro
       - /etc/letsencrypt/:/etc/letsencrypt/:ro
       - ./docker/certs/ca.cert:/etc/pki/tls/certs/ca.cert:ro
       - ./docker/certs/ca.cert:/etc/pki/ca-trust/source/anchors/ca.cert:ro
diff --git a/docker/kolab/utils/100-update-roundcube.sh b/docker/kolab/utils/100-update-roundcube.sh
new file mode 100755
--- /dev/null
+++ b/docker/kolab/utils/100-update-roundcube.sh
@@ -0,0 +1,18 @@
+#!/bin/bash
+# This is incomplete and clearly not how it's supposed to be done,
+# but it will work for now.
+
+cp -Rf /src/roundcubemail/program /usr/share/roundcubemail/program
+
+pushd /src/roundcubemail-plugins-kolab/plugins
+cp -f calendar/*.js /usr/share/roundcubemail/public_html/assets/plugins/calendar/
+find calendar/ -type f \( -name "*.php" -o -name "*.inc" \) ! -name config.inc.php -exec cp -v {} /usr/share/roundcubemail/plugins/{} \;
+
+find libcalendaring/ -type f \( -name "*.php" -o -name "*.inc" \) ! -name config.inc.php -exec cp -v {} /usr/share/roundcubemail/plugins/{} \;
+cp -f libcalendaring/*.js /usr/share/roundcubemail/public_html/assets/plugins/libcalendaring/
+
+find libkolab/ -type f \( -name "*.php" -o -name "*.inc" \) ! -name config.inc.php -exec cp -v {} /usr/share/roundcubemail/plugins/{} \;
+cp -f libkolab/*.js /usr/share/roundcubemail/public_html/assets/plugins/libkolab/
+popd
+
+systemctl reload httpd
diff --git a/docker/kolab/utils/101-update-pykolab.sh b/docker/kolab/utils/101-update-pykolab.sh
new file mode 100755
--- /dev/null
+++ b/docker/kolab/utils/101-update-pykolab.sh
@@ -0,0 +1,8 @@
+#!/bin/bash
+
+cp /usr/lib/python2.7/site-packages/pykolab/constants.py /tmp/constants.py
+cp -Rf /src/pykolab/pykolab /usr/lib/python2.7/site-packages/
+cp /tmp/constants.py /usr/lib/python2.7/site-packages/pykolab/constants.py
+
+systemctl restart wallace
+systemctl restart kolabd
diff --git a/docker/kolab/utils/102-enable-xdebug.sh b/docker/kolab/utils/102-enable-xdebug.sh
new file mode 100755
--- /dev/null
+++ b/docker/kolab/utils/102-enable-xdebug.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+yum -y install php-xdebug
+
+cat << EOF > /etc/php.d/xdebug.ini
+zend_extension=/usr/lib64/php/modules/xdebug.so
+
+# Profiler config for xdebug3
+#xdebug.mode=profile
+#xdebug.output_dir="/tmp/"
+#xdebug.start_with_request=trigger
+
+# Profiler config for xdebug2
+#xdebug.remote_log="/tmp/xdebug.log"
+xdebug.profiler_enable = 0
+# Enable using a XDEBUG_PROFILE GET/POST parameter
+xdebug.profiler_enable_trigger = 1
+xdebug.profiler_output_dir = "/tmp/"
+#xdebug.remote_enable=on
+#xdebug.remote_port=9000
+#xdebug.remote_autostart=0
+#xdebug.remote_connect_back=on
+#xdebug.idekey=editor-xdebug
+EOF
diff --git a/ext/.gitignore b/ext/.gitignore
new file mode 100644
--- /dev/null
+++ b/ext/.gitignore
@@ -0,0 +1 @@
+*
diff --git a/ext/README.md b/ext/README.md
new file mode 100644
--- /dev/null
+++ b/ext/README.md
@@ -0,0 +1,3 @@
+Use this directory to clone external git repositories (roundcubemail, roundcubemail-plugins-kolab, pykolab).
+
+This can then be used for a development setup.