diff --git a/doc/docker/README.md b/doc/docker/README.md
index c70d04e217..1e6fe4fc8f 100644
--- a/doc/docker/README.md
+++ b/doc/docker/README.md
@@ -17,6 +17,7 @@ The provided docker-compose.yml will run the following container:
 * **collabora-key** Collabora Online Office
 * **rocketchat** Rocket.Chat server
 * **rocketchat-mongodb** MongoDB for Rocket.Chat
+* **portainer** Portainer Docker GUI
 ```
 version: '3'
 volumes:
@@ -155,12 +156,12 @@ services:
     # for email notifications add your email and mail-server here
     #- WATCHTOWER_NOTIFICATIONS=email
     #- WATCHTOWER_NOTIFICATIONS_LEVEL=info # possible values: panic, fatal, error, warn, info or debug
-    #- WATCHTOWER_NOTIFICATION_EMAIL_FROM="watchtower@my-domain.com"
-    #- WATCHTOWER_NOTIFICATION_EMAIL_TO="me@my-domain.com"
+    #- WATCHTOWER_NOTIFICATION_EMAIL_FROM=watchtower@my-domain.com
+    #- WATCHTOWER_NOTIFICATION_EMAIL_TO=me@my-domain.com
     #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER="mail.my-domain.com" # if you give your MX here, you need no user/password
     #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT=25
-    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER="watchtower@my-domain.com"
-    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD="secret"
+    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=watchtower@my-domain.com
+    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD=secret
     command: --schedule "0 0 4 * * *"
     container_name: egroupware-watchtower
     restart: always
@@ -226,4 +227,17 @@ services:
     command: 'bash -c "for i in `seq 1 30`; do mongo mongo/rocketchat --eval \"rs.initiate({ _id: ''rs0'', members: [ { _id: 0, host: ''localhost:27017'' } ]})\" && s=$$? && break || s=$$?; echo \"Tried $$i times. Waiting 5 secs...\"; sleep 5; done; (exit $$s)"'
     depends_on:
       - mongo
+
+  # Portainer: Docker GUI (needs to be enabled in nginx.conf too!)
+  #portainer:
+  #  image: portainer/portainer
+  #  command: -H unix:///var/run/docker.sock
+  #  restart: always
+  #  ports:
+  #    - 9000:9000
+  #    - 8000:8000
+  #  volumes:
+  #    - /var/run/docker.sock:/var/run/docker.sock
+  #    - portainer_data:/data
+  #  container_name: portainer
 ```
diff --git a/doc/docker/development/build.sh b/doc/docker/development/build.sh
index c097e67aae..888285394d 100755
--- a/doc/docker/development/build.sh
+++ b/doc/docker/development/build.sh
@@ -7,7 +7,7 @@ RECOMMENDED_PHP_VERSION=7.3
 
 PHP_VERSION=${1:-7.3}
 
-TAG=$(docker run --rm -i --entrypoint bash $REPO/$IMAGE -c "apt update && apt search php$PHP_VERSION-fpm" 2>/dev/null|grep php$PHP_VERSION-fpm|sed "s|^php$PHP_VERSION-fpm/bionic.*\(7\.[0-9]*\.[0-9]*\).*|\1|g")
+TAG=$(docker run --rm -i --entrypoint bash $REPO/$IMAGE -c "apt update && apt search php$PHP_VERSION-fpm" 2>/dev/null|grep php$PHP_VERSION-fpm|sed "s|^php$PHP_VERSION-fpm/bionic.?*\(7\.[0-9]*\.[0-9]*\).*|\1|g")
 test -z "$TAG" && {
 	echo "Can't get new tag of $REPO/$IMAGE container --> existing"
 	exit 1
diff --git a/doc/docker/development/docker-compose.yml b/doc/docker/development/docker-compose.yml
index f59c0024ac..37ddf7d0f5 100644
--- a/doc/docker/development/docker-compose.yml
+++ b/doc/docker/development/docker-compose.yml
@@ -248,3 +248,16 @@ services:
     command: 'bash -c "for i in `seq 1 30`; do mongo mongo/rocketchat --eval \"rs.initiate({ _id: ''rs0'', members: [ { _id: 0, host: ''localhost:27017'' } ]})\" && s=$$? && break || s=$$?; echo \"Tried $$i times. Waiting 5 secs...\"; sleep 5; done; (exit $$s)"'
     depends_on:
       - mongo
+
+  # Portainer: Docker GUI (needs to be enabled in nginx.conf too!)
+#   portainer:
+#    image: portainer/portainer
+#    command: -H unix:///var/run/docker.sock
+#    restart: always
+#    ports:
+#      - 9000:9000
+#      - 8000:8000
+#    volumes:
+#      - /var/run/docker.sock:/var/run/docker.sock
+#      - portainer_data:/data
+#    container_name: portainer
diff --git a/doc/docker/development/nginx.conf b/doc/docker/development/nginx.conf
index 48424b0c64..048fe4a3ce 100644
--- a/doc/docker/development/nginx.conf
+++ b/doc/docker/development/nginx.conf
@@ -136,7 +136,6 @@ server {
 		proxy_set_header Host $http_host;
 	}
 
-	# Rocket.Chat sniplet meant to be included in server block of EGroupware vhost
 	# proxy into rocketchat container
 	location /rocketchat {
 		proxy_pass http://rocketchat:3000;
@@ -144,4 +143,12 @@ server {
 		proxy_set_header Connection "upgrade";
 		proxy_set_header Host $http_host;
 	}
+
+    # Portainer: Docker GUI (needs to be enabled in docker-compose.yml too!)
+    #location /portainer/ {
+    #    proxy_pass http://portainer:9000/;
+    #    proxy_set_header Upgrade $http_upgrade;
+    #    proxy_set_header Connection "upgrade";
+    #    proxy_set_header Host $http_host;
+    #}
 }
diff --git a/doc/docker/docker-compose.yml b/doc/docker/docker-compose.yml
index a68ea6f80d..b29385d037 100644
--- a/doc/docker/docker-compose.yml
+++ b/doc/docker/docker-compose.yml
@@ -137,11 +137,11 @@ services:
     # for email notifications add your email and mail-server here
     #- WATCHTOWER_NOTIFICATIONS=email
     #- WATCHTOWER_NOTIFICATIONS_LEVEL=info # possible values: panic, fatal, error, warn, info or debug
-    #- WATCHTOWER_NOTIFICATION_EMAIL_FROM="watchtower@my-domain.com"
-    #- WATCHTOWER_NOTIFICATION_EMAIL_TO="me@my-domain.com"
-    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER="mail.my-domain.com" # if you give your MX here, you need no user/password
+    #- WATCHTOWER_NOTIFICATION_EMAIL_FROM=watchtower@my-domain.com
+    #- WATCHTOWER_NOTIFICATION_EMAIL_TO=me@my-domain.com"
+    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER=mail.my-domain.com # if you give your MX here, you need no user/password
     #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT=25
-    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER="watchtower@my-domain.com"
+    #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=watchtower@my-domain.com
     #- WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD="secret"
     command: --schedule "0 0 4 * * *"
     container_name: egroupware-watchtower
@@ -208,3 +208,16 @@ services:
     command: 'bash -c "for i in `seq 1 30`; do mongo mongo/rocketchat --eval \"rs.initiate({ _id: ''rs0'', members: [ { _id: 0, host: ''localhost:27017'' } ]})\" && s=$$? && break || s=$$?; echo \"Tried $$i times. Waiting 5 secs...\"; sleep 5; done; (exit $$s)"'
     depends_on:
       - mongo
+
+  # Portainer: Docker GUI (needs to be enabled in nginx.conf too!)
+#   portainer:
+#    image: portainer/portainer
+#    command: -H unix:///var/run/docker.sock
+#    restart: always
+#    ports:
+#      - 9000:9000
+#      - 8000:8000
+#    volumes:
+#      - /var/run/docker.sock:/var/run/docker.sock
+#      - portainer_data:/data
+#    container_name: portainer
diff --git a/doc/docker/nginx.conf b/doc/docker/nginx.conf
index c84f5b7a6f..5749c42073 100644
--- a/doc/docker/nginx.conf
+++ b/doc/docker/nginx.conf
@@ -147,7 +147,6 @@ server {
 		proxy_set_header Host $http_host;
 	}
 
-	# Rocket.Chat sniplet meant to be included in server block of EGroupware vhost
 	# proxy into rocketchat container
 	location /rocketchat {
 		proxy_pass http://rocketchat:3000;
@@ -155,4 +154,12 @@ server {
 		proxy_set_header Connection "upgrade";
 		proxy_set_header Host $http_host;
 	}
+
+    # Portainer: Docker GUI (needs to be enabled in docker-compose.yml too!)
+    #location /portainer/ {
+    #    proxy_pass http://portainer:9000/;
+    #    proxy_set_header Upgrade $http_upgrade;
+    #    proxy_set_header Connection "upgrade";
+    #    proxy_set_header Host $http_host;
+    #}
 }