diff --git a/conf/hostname.conf.sample b/conf/hostname.conf.sample
index 8eee749..f3916e1 100644
--- a/conf/hostname.conf.sample
+++ b/conf/hostname.conf.sample
@@ -17,6 +17,15 @@ WEBSITE="<site-name-of-cloud-instance>"
 #THIRD_PARTY_APPS="calendar contacts notes richdocuments"
 
 
+# - Extra Apps
+# -
+# - Possible values are app-names like 'calendar' , 'contacts' , ..
+# -
+# - a blank separated list enclosed in brackets 
+# -
+#EXTRA_APPS="(calendar contacts deck notes richdocuments tasks)"
+
+
 # - Source directory for tar archives of Nextcloud
 # -
 # - Defaults to '/usr/local/src/nextcloud'
diff --git a/install_apps.sh b/install_apps.sh
new file mode 100755
index 0000000..6c78905
--- /dev/null
+++ b/install_apps.sh
@@ -0,0 +1,812 @@
+#!/usr/bin/env bash
+
+CUR_IFS=$IFS
+
+script_name="$(basename $(realpath $0))"
+script_dir="$(dirname $(realpath $0))"
+
+conf_dir="${script_dir}/conf"
+snippet_dir="${script_dir}/snippets"
+
+declare -a unsorted_website_arr
+declare -a website_arr
+
+log_file="$(mktemp)"
+
+backup_date=$(date +%Y-%m-%d-%H%M)
+
+
+# =============
+# --- Some functions
+# =============
+
+clean_up() {
+
+
+   if [[ -f "$_backup_crontab_file" ]]; then
+
+      echononl "   (Re)Install previously saved crontab .."
+
+      crontab $_backup_crontab_file >> $log_file 2>&1
+
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+			error "$(cat $log_file)"
+      fi
+
+   fi
+
+   # Perform program exit housekeeping
+   rm -f $log_file
+   blank_line
+   exit $1
+}
+
+is_number() {
+
+   return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);
+
+   # - also possible
+   # -
+   #[[ ! -z "${1##*[!0-9]*}" ]] && return 0 || return 1
+   #return $([[ ! -z "${1##*[!0-9]*}" ]])
+}
+
+echononl(){
+   echo X\\c > /tmp/shprompt$$
+   if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
+      echo -e -n "$*\\c" 1>&2
+   else
+       echo -e -n "$*" 1>&2
+   fi
+   rm /tmp/shprompt$$
+}
+echo_done() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[32mdone\033[m ]"
+   else
+      echo " [ done ]"
+   fi
+}
+echo_ok() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[32mok\033[m ]"
+   else
+      echo " [ ok ]"
+   fi
+}
+echo_warning() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[33m\033[1mwarn\033[m ]"
+   else
+      echo " [ warning ]"
+   fi
+}
+echo_failed(){
+   if $terminal ; then
+      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
+   else
+      echo ' [ failed! ]'
+   fi
+}
+echo_skipped() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[37mskipped\033[m ]"
+   else
+      echo " [ skipped ]"
+   fi
+}
+fatal (){
+   echo ""
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[31m\033[1mFatal\033[m ]: \033[37m\033[1m$*\033[m"
+      echo ""
+      echo -e "\t\033[31m\033[1m           Script will be interrupted..\033[m\033[m"
+   else
+      echo "fatal: $*"
+      echo "Script will be interrupted.."
+   fi
+   clean_up 1
+}
+
+error(){
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[31m\033[1mFehler\033[m ]: $*"
+   else
+      echo "Error: $*"
+   fi
+   echo ""
+}
+
+warn (){
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[33m\033[1mWarning\033[m ]: $*"
+   else
+      echo "Warning: $*"
+   fi
+   echo ""
+}
+
+info (){
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[32m\033[1mInfo\033[m ]: $*"
+   else
+      echo "Info: $*"
+   fi
+   echo ""
+}
+
+## - Check if a given array (parameter 2) contains a given string (parameter 1)
+## -
+containsElement () {
+   local e
+   for e in "${@:2}"; do [[ "$e" == "$1" ]] && return 0; done
+   return 1
+}
+
+blank_line() {
+   if $terminal ; then
+      echo ""
+   fi
+}
+
+ensure_nc_app() {
+
+   local APP_ID="$1"
+
+   echononl "   Install nextcloud app '$APP_ID'.."
+
+   # 1. Prüfen, ob die App überhaupt installiert ist
+   #
+   # ${OCC_CMD[@]} expandiert jedes Element des Arrays als eigenes Argument.
+   #
+   if ! "${OCC_CMD[@]}" app:list 2>/dev/null | grep -q " - ${APP_ID}:"; then
+
+      "${OCC_CMD[@]}" app:install "$APP_ID" > $log_file 2>&1
+
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+
+         echo -e "\ncommand was: ${OCC_CMD[@]} app:install \"${APP_ID}\""
+
+         error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+         [[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+
+   else
+      echo_skipped
+   fi
+
+   echononl "   Enable App  '${APP_ID}'.."
+   # 2. Prüfen, ob die App aktiviert ist (nur 'Enabled'-Block betrachten)
+   local ENABLED_BLOCK
+   ENABLED_BLOCK="$("${OCC_CMD[@]}" app:list 2>/dev/null \
+      | awk 'BEGIN{flag=0} /Enabled:/ {flag=1; next} /Disabled:/ {flag=0} flag')"
+
+   if echo "$ENABLED_BLOCK" | grep -q " - ${APP_ID}:"; then
+      echo_skipped
+   else
+      "${OCC_CMD[@]}" app:enable "${APP_ID}" > $log_file 2>&1
+
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+
+         echo -e "\ncommand was: ${OCC_CMD[@]} app:install \"${APP_ID}\""
+
+         error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+         [[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+
+   fi
+
+}
+
+
+
+# ----------
+# - Jobhandling 
+# ----------
+
+# - Run 'clean_up' for signals SIGHUP SIGINT SIGTERM
+# -
+trap clean_up SIGHUP SIGINT SIGTERM
+
+## - 
+while IFS='' read -r -d '' _conf_file ; do
+   source $_conf_file
+   if [[ -n "$WEBSITE" ]] ; then
+      unsorted_website_arr+=("${WEBSITE}:$_conf_file")
+   fi
+   WEBSITE=""
+done  < <(find "${conf_dir}" -maxdepth 1 -type f -name "*.conf" -print0)
+#done  < <(find "${conf_dir}" -maxdepth 1 -type f -name "create_missing_indices_*.conf" -print0)
+
+#if [[ ${#unsorted_website_arr} -eq 0 ]]; then
+#   fatal "No configuration files found in '${script_dir}/conf' or no website configured!"
+#fi
+
+# - Sort array
+# -
+IFS=$'\n' website_arr=($(sort <<<"${unsorted_website_arr[*]}"))
+
+
+# - Reset IFS
+# -
+IFS=$CUR_IFS
+
+
+# =============
+# --- Some 
+# =============
+
+# - Support systemd ?
+# -
+if [[ "X$(which systemd)" = "X" ]]; then
+   SYSTEMD_EXISTS=false
+else
+   SYSTEMD_EXISTS=true
+fi
+
+# - Running in a terminal?
+# -
+if [[ -t 1 ]] ; then
+      terminal=true
+else
+   terminal=false
+fi
+
+clear
+
+echo ""
+echo -e "\033[32m-----\033[m"
+echo "Add missing columns"
+echo -e "\033[32m-----\033[m"
+
+# Which cloud instance (website) would you like to update
+#
+source ${snippet_dir}/get-cloud-instance-to-update.sh
+
+
+# - Reset IFS
+# -
+IFS=$CUR_IFS
+
+
+echo ""
+echononl "   Include Configuration file.."
+if [[ ! -f $conf_file ]]; then
+   echo_failed
+   fatal "Missing configuration file '$conf_file'."
+else
+   source $conf_file
+   echo_ok
+fi
+echo ""
+
+
+
+# =============
+# --- Some checks
+# =============
+
+DEFAULT_SRC_BASE_DIR="/usr/local/src/nextcloud"
+DEFAULT_HTTP_USER="www-data"
+DEFAULT_HTTP_GROUP="www-data"
+DEFAULT_PHP_ENGINE="FPM"
+
+
+if [[ -z ${WEBSITE} ]] ; then
+   WEBSITE="$DEFAULT_WEBSITE"
+fi
+
+DEFAULT_WEB_BASE_DIR="/var/www/$WEBSITE"
+
+[[ -n "$WEB_BASE_DIR" ]] || WEB_BASE_DIR=$DEFAULT_WEB_BASE_DIR
+
+if [[ ! -d ${WEB_BASE_DIR} ]] ; then
+   fatal "Web base directory not found (parameter 'WEB_BASE_DIR')"
+fi
+
+if [[ -z "${EXTRA_APPS}" ]]; then
+   fatal "No list of extra apps (parameter EXTRA_APPS) found!"
+fi
+
+[[ -n "$PHP_ENGINE" ]] || PHP_ENGINE=$DEFAULT_PHP_ENGINE
+
+if [[ "$DATABASE_TYPE" != "postgres" ]] && [[ "$DATABASE_TYPE" != "mysql" ]]; then
+   fatal "Wrong or missing database type (parameter 'DATABASE_TYPE')"
+fi
+
+if [[ -z "$DATABASE_NAME" ]]; then
+   fatal "Missing database name (parameter 'DATABASE_NAME')"
+fi
+
+if [[ "$DATABASE_TYPE" = "mysql" ]] && [[ -z "$MYSQL_CREDENTIALS" ]]; then
+   fatal "No Database Credentials for MySQL given (parameter 'MYSQL_CREDENTIALS')"
+fi
+
+if [[ "$DATABASE_TYPE" = "postgres" ]]; then
+   if [[ -z "$PSQL_USER" ]] || [[ -z "$PSQL_PASS" ]]; then
+      fatal "No Database Credentials for PostgreSQL given (parameters: 'PSQL_USER' 'PSQL_PASS'"
+   fi
+fi
+
+NGINX_IS_ENABLED=false
+APACHE2_IS_ENABLED=false
+
+# Get Webservice environment as IS_HTTPD_RUNNING, HTTP_USER, HTTP_GROUP..
+#
+source ${snippet_dir}/get-webservice-environment.sh
+
+# Check PHP Version
+#
+source ${snippet_dir}/get-php-major-version.sh
+
+
+# Get full qualified PHP command
+#
+source ${snippet_dir}/get-path-of-php-command.sh
+
+
+CURRENT_INSTALL_DIR="$(realpath ${WEB_BASE_DIR}/nextcloud)"
+CURRENT_VERSION="$(basename $CURRENT_INSTALL_DIR | cut -d"-" -f2)"
+
+# OCC_CMD Kommando als Array definieren.
+#
+# Ausführen des Kommandos:
+#
+#  ${OCC_CMD[@]}
+#
+# ${OCC_CMD[@]} ist die einzig sichere Art, ein Array als Kommando aufzurufen.  Jedes Element
+# des Arrays als eigenes Argument.
+#
+OCC_CMD=(sudo -u "$HTTP_USER" "$PHP_BIN" -f "${CURRENT_INSTALL_DIR}/occ")
+
+echo ""
+echo -e "\033[1;32mStarting Script $script_name for \033[1;37m${WEBSITE}\033[m"
+echo ""
+echo -e   "   Website to update....................: $WEBSITE"
+echo ""
+echo -e   "   Nextcloud version....................: $CURRENT_VERSION"
+echo ""
+echo -e   "   Extra apps...........................: ${EXTRA_APPS[@]}"
+echo ""
+echo -e   "   Web base directory...................: $WEB_BASE_DIR"
+echo ""
+echo -e   "   Webserver user.......................: $HTTP_USER"
+echo -e   "   Webserver group......................: $HTTP_GROUP"
+echo ""
+echo -e   "   PHP version..........................: $PHP_VERSION"
+echo -e   "   PHP Engine...........................: $PHP_ENGINE"
+echo ""
+echo -e   "   PHP Command..........................: $PHP_BIN"
+
+echo ""
+echo -n "   Type upper case 'YES' to continue executing with this parameters: "
+read OK
+if [[ "$OK" = "YES" ]] ; then
+   echo ""
+   echo ""
+   echo -e "\033[1;32mGoing to update Nextcloud on \033[1;37m$WEBSITE \033[m"
+   echo ""
+else
+   fatal "Abort by user request - Answer as not 'YES'"
+fi
+
+
+echo ""
+
+
+# -----
+# - Do some pre-update tasks..
+# -----
+
+echo ""
+echo ""
+echo -e "\033[37m\033[1mDo some pre-update tasks..\033[m"
+echo ""
+
+# - Deaktiviere Cronjobs
+# -
+_backup_crontab_file=/tmp/crontab_root.${backup_date}
+echononl "   Backup Crontab to '$_backup_crontab_file'"
+crontab -l > $_backup_crontab_file 2> $log_file
+if [[ $? -eq 0 ]]; then
+   echo_ok
+else
+   echo_failed
+   fatal "$(cat $log_file)"
+fi
+
+echononl "   Remove crontab for root.."
+crontab -r > $log_file 2>&1
+if [[ $? -eq 0 ]]; then
+   echo_ok
+else
+   echo_failed
+   fatal "$(cat $log_file)"
+fi
+
+
+# - Stop Apache Webserver
+# -
+echo ""
+echononl "   Stop Apache Webserver.."
+if $APACHE2_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl stop apache2
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/apache2 stop
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      fi
+   else
+      echo_skipped
+   fi
+else
+   echo_skipped
+fi
+
+# - Stop Nginx Webservice
+# -
+echo ""
+echononl "   Stop Nginx Webserver.."
+if $NGINX_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl stop nginx
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/nginx stop
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      fi
+   else
+      echo_skipped
+   fi
+fi
+
+echo ""
+
+# - Backup Database
+# -
+echononl "   Backup MySQL database '$DATABASE_NAME'.."
+if [[ "$DATABASE_TYPE" = 'mysql' ]]; then
+   mysqldump $MYSQL_CREDENTIALS --max_allowed_packet=128M --single-transaction $DATABASE_NAME > \
+      ${WEB_BASE_DIR}/${DATABASE_NAME}-v${CURRENT_VERSION}.${backup_date}.sql 2> $log_file
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+
+      blank_line
+      echo -e "\t[ \033[33m\033[1mCommand\033[m ]: \033[37m\033[1mmysqldump $MYSQL_CREDENTIALS \\
+\t                --max_allowed_packet=128M --single-transaction $DATABASE_NAME > \\
+\t                ${WEB_BASE_DIR}/${DATABASE_NAME}-v${PRIOR_VERSION}.${backup_date}.sql\033[m"
+
+      error "$(cat $log_file)"
+
+      echononl "continue anyway [yes/no]: "
+      read OK
+      OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+      while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+         echononl "Wrong entry! - repeat [yes/no]: "
+         read OK
+      done
+      [[ $OK = "yes" ]] || fatal "Abbruch durch User"
+      blank_line
+
+   fi
+elif [[ "$DATABASE_TYPE" = 'postgres' ]]; then
+   PGPASSWORD=$PSQL_PASS \
+   pg_dump $DATABASE_NAME -h $PSQL_SERVER -U $PSQL_USER  \
+      -f ${WEB_BASE_DIR}/${DATABASE_NAME}-v${CURRENT_VERSION}.${backup_date}.sql 2> $log_file
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      fatal "$(cat $log_file)"
+   fi
+fi
+
+echo
+
+
+# -----
+# - Main part of the script
+# -----
+
+echo ""
+echo ""
+echo -e "\033[37m\033[1mMain part of the script\033[m"
+echo ""
+
+declare -i index=1
+for APP in "${EXTRA_APPS[@]}"; do
+   [[ ${index} -gt 1 ]] && blank_line
+  ensure_nc_app "$APP"
+  (( index++ ))
+done
+
+
+
+# -----
+# - Doing some post-update tasks
+# -----
+
+echo ""
+echo ""
+echo -e "\033[37m\033[1mDoing some post-update tasks..\033[m"
+
+echo ""
+echononl "   Restart PHP engine.."
+if [[ "$PHP_ENGINE" = "FPM" ]]; then
+   if $SYSTEMD_EXISTS ; then
+      systemctl restart php-${PHP_VERSION}-fpm > $log_file 2>&1
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+			error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+   		[[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+   else
+      /etc/init.d/php-${PHP_VERSION}-fpm restart > $log_file 2>&1
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+			error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+   		[[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+   fi
+else
+   echo_skipped
+fi
+
+# - Start Apache Webserver
+# -
+echo ""
+echononl "   Start Apache Webserver.."
+if $APACHE2_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl start apache2 > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/apache2 start > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+         fi
+      fi
+   else
+      echo_skipped
+      warn "The webserver was not running, so it will be keept down!"
+   fi
+else
+   echo_skipped
+fi
+
+
+# - Start NGINX Webservise
+# -
+echo ""
+echononl "   Start Nginx Webserver.."
+if $NGINX_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl start nginx > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/nginx start > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+         fi
+      fi
+   else
+      echo_skipped
+      warn "The NGINX is not configured as active - so nothing to do."
+   fi
+else
+   echo_skipped
+fi
+
+_redis_cli_bin="$(which redis-cli)"
+if [[ -z "$_redis_cli_bin" ]]; then
+   if [[ -x "/usr/local/bin/redis-cli" ]]; then
+      _redis_cli_bin="/usr/local/bin/redis-cli"
+   fi
+fi
+
+
+echononl "   Flush redis cache.."
+if [[ -x "$_redis_cli_bin" ]]; then
+   $_redis_cli_bin flushall > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      error "$(cat $log_file)"
+   fi
+else
+   echo_skipped
+fi
+
+
+echononl "   Restart redis server.."
+if $SYSTEMD_EXISTS ; then
+   systemctl restart redis-server > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      error "$(cat $log_file)"
+   fi
+else
+   /etc/init.d/redis-server restart  > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      error "$(cat $log_file)"
+   fi
+fi
+
+blank_line
+clean_up 0
diff --git a/remove-app_api.sh b/remove-app_api.sh
new file mode 100755
index 0000000..13d8d9b
--- /dev/null
+++ b/remove-app_api.sh
@@ -0,0 +1,750 @@
+#!/usr/bin/env bash
+
+CUR_IFS=$IFS
+
+script_name="$(basename $(realpath $0))"
+script_dir="$(dirname $(realpath $0))"
+
+conf_dir="${script_dir}/conf"
+snippet_dir="${script_dir}/snippets"
+
+declare -a unsorted_website_arr
+declare -a website_arr
+
+log_file="$(mktemp)"
+
+backup_date=$(date +%Y-%m-%d-%H%M)
+
+
+# =============
+# --- Some functions
+# =============
+
+clean_up() {
+
+
+   if [[ -f "$_backup_crontab_file" ]]; then
+
+      echononl "   (Re)Install previously saved crontab .."
+
+      crontab $_backup_crontab_file >> $log_file 2>&1
+
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+			error "$(cat $log_file)"
+      fi
+
+   fi
+
+   # Perform program exit housekeeping
+   rm -f $log_file
+   blank_line
+   exit $1
+}
+
+is_number() {
+
+   return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);
+
+   # - also possible
+   # -
+   #[[ ! -z "${1##*[!0-9]*}" ]] && return 0 || return 1
+   #return $([[ ! -z "${1##*[!0-9]*}" ]])
+}
+
+echononl(){
+   echo X\\c > /tmp/shprompt$$
+   if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
+      echo -e -n "$*\\c" 1>&2
+   else
+       echo -e -n "$*" 1>&2
+   fi
+   rm /tmp/shprompt$$
+}
+echo_done() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[32mdone\033[m ]"
+   else
+      echo " [ done ]"
+   fi
+}
+echo_ok() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[32mok\033[m ]"
+   else
+      echo " [ ok ]"
+   fi
+}
+echo_warning() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[33m\033[1mwarn\033[m ]"
+   else
+      echo " [ warning ]"
+   fi
+}
+echo_failed(){
+   if $terminal ; then
+      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
+   else
+      echo ' [ failed! ]'
+   fi
+}
+echo_skipped() {
+   if $terminal ; then
+      echo -e "\033[75G[ \033[37mskipped\033[m ]"
+   else
+      echo " [ skipped ]"
+   fi
+}
+fatal (){
+   echo ""
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[31m\033[1mFatal\033[m ]: \033[37m\033[1m$*\033[m"
+      echo ""
+      echo -e "\t\033[31m\033[1m           Script will be interrupted..\033[m\033[m"
+   else
+      echo "fatal: $*"
+      echo "Script will be interrupted.."
+   fi
+   clean_up 1
+}
+
+error(){
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[31m\033[1mFehler\033[m ]: $*"
+   else
+      echo "Error: $*"
+   fi
+   echo ""
+}
+
+warn (){
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[33m\033[1mWarning\033[m ]: $*"
+   else
+      echo "Warning: $*"
+   fi
+   echo ""
+}
+
+info (){
+   echo ""
+   if $terminal ; then
+      echo -e "\t[ \033[32m\033[1mInfo\033[m ]: $*"
+   else
+      echo "Info: $*"
+   fi
+   echo ""
+}
+
+## - Check if a given array (parameter 2) contains a given string (parameter 1)
+## -
+containsElement () {
+   local e
+   for e in "${@:2}"; do [[ "$e" == "$1" ]] && return 0; done
+   return 1
+}
+
+blank_line() {
+   if $terminal ; then
+      echo ""
+   fi
+}
+
+
+
+# ----------
+# - Jobhandling 
+# ----------
+
+# - Run 'clean_up' for signals SIGHUP SIGINT SIGTERM
+# -
+trap clean_up SIGHUP SIGINT SIGTERM
+
+## - 
+while IFS='' read -r -d '' _conf_file ; do
+   source $_conf_file
+   if [[ -n "$WEBSITE" ]] ; then
+      unsorted_website_arr+=("${WEBSITE}:$_conf_file")
+   fi
+   WEBSITE=""
+done  < <(find "${conf_dir}" -maxdepth 1 -type f -name "*.conf" -print0)
+#done  < <(find "${conf_dir}" -maxdepth 1 -type f -name "create_missing_indices_*.conf" -print0)
+
+#if [[ ${#unsorted_website_arr} -eq 0 ]]; then
+#   fatal "No configuration files found in '${script_dir}/conf' or no website configured!"
+#fi
+
+# - Sort array
+# -
+IFS=$'\n' website_arr=($(sort <<<"${unsorted_website_arr[*]}"))
+
+
+# - Reset IFS
+# -
+IFS=$CUR_IFS
+
+
+# =============
+# --- Some 
+# =============
+
+# - Support systemd ?
+# -
+if [[ "X$(which systemd)" = "X" ]]; then
+   SYSTEMD_EXISTS=false
+else
+   SYSTEMD_EXISTS=true
+fi
+
+# - Running in a terminal?
+# -
+if [[ -t 1 ]] ; then
+      terminal=true
+else
+   terminal=false
+fi
+
+clear
+
+echo ""
+echo -e "\033[32m-----\033[m"
+echo "Add missing columns"
+echo -e "\033[32m-----\033[m"
+
+# Which cloud instance (website) would you like to update
+#
+source ${snippet_dir}/get-cloud-instance-to-update.sh
+
+
+# - Reset IFS
+# -
+IFS=$CUR_IFS
+
+
+echo ""
+echononl "   Include Configuration file.."
+if [[ ! -f $conf_file ]]; then
+   echo_failed
+   fatal "Missing configuration file '$conf_file'."
+else
+   source $conf_file
+   echo_ok
+fi
+echo ""
+
+
+
+# =============
+# --- Some checks
+# =============
+
+DEFAULT_SRC_BASE_DIR="/usr/local/src/nextcloud"
+DEFAULT_HTTP_USER="www-data"
+DEFAULT_HTTP_GROUP="www-data"
+DEFAULT_PHP_ENGINE="FPM"
+
+
+if [[ -z ${WEBSITE} ]] ; then
+   WEBSITE="$DEFAULT_WEBSITE"
+fi
+
+DEFAULT_WEB_BASE_DIR="/var/www/$WEBSITE"
+
+[[ -n "$WEB_BASE_DIR" ]] || WEB_BASE_DIR=$DEFAULT_WEB_BASE_DIR
+
+if [[ ! -d ${WEB_BASE_DIR} ]] ; then
+   fatal "Web base directory not found (parameter 'WEB_BASE_DIR')"
+fi
+
+[[ -n "$PHP_ENGINE" ]] || PHP_ENGINE=$DEFAULT_PHP_ENGINE
+
+if [[ "$DATABASE_TYPE" != "postgres" ]] && [[ "$DATABASE_TYPE" != "mysql" ]]; then
+   fatal "Wrong or missing database type (parameter 'DATABASE_TYPE')"
+fi
+
+if [[ -z "$DATABASE_NAME" ]]; then
+   fatal "Missing database name (parameter 'DATABASE_NAME')"
+fi
+
+if [[ "$DATABASE_TYPE" = "mysql" ]] && [[ -z "$MYSQL_CREDENTIALS" ]]; then
+   fatal "No Database Credentials for MySQL given (parameter 'MYSQL_CREDENTIALS')"
+fi
+
+if [[ "$DATABASE_TYPE" = "postgres" ]]; then
+   if [[ -z "$PSQL_USER" ]] || [[ -z "$PSQL_PASS" ]]; then
+      fatal "No Database Credentials for PostgreSQL given (parameters: 'PSQL_USER' 'PSQL_PASS'"
+   fi
+fi
+
+NGINX_IS_ENABLED=false
+APACHE2_IS_ENABLED=false
+
+# Get Webservice environment as IS_HTTPD_RUNNING, HTTP_USER, HTTP_GROUP..
+#
+source ${snippet_dir}/get-webservice-environment.sh
+
+# Check PHP Version
+#
+source ${snippet_dir}/get-php-major-version.sh
+
+
+# Get full qualified PHP command
+#
+source ${snippet_dir}/get-path-of-php-command.sh
+
+
+CURRENT_INSTALL_DIR="$(realpath ${WEB_BASE_DIR}/nextcloud)"
+CURRENT_VERSION="$(basename $CURRENT_INSTALL_DIR | cut -d"-" -f2)"
+
+echo ""
+echo -e "\033[1;32mStarting Script $script_name for \033[1;37m${WEBSITE}\033[m"
+echo ""
+echo -e   "   Website to update....................: $WEBSITE"
+echo ""
+echo -e   "   Nextcloud version....................: $CURRENT_VERSION"
+echo ""
+echo -e   "   Web base directory...................: $WEB_BASE_DIR"
+echo ""
+echo -e   "   Webserver user.......................: $HTTP_USER"
+echo -e   "   Webserver group......................: $HTTP_GROUP"
+echo ""
+echo -e   "   PHP version..........................: $PHP_VERSION"
+echo -e   "   PHP Engine...........................: $PHP_ENGINE"
+echo ""
+echo -e   "   PHP Command..........................: $PHP_BIN"
+
+echo ""
+echo -n "   Type upper case 'YES' to continue executing with this parameters: "
+read OK
+if [[ "$OK" = "YES" ]] ; then
+   echo ""
+   echo ""
+   echo -e "\033[1;32mGoing to update Nextcloud on \033[1;37m$WEBSITE \033[m"
+   echo ""
+else
+   fatal "Abort by user request - Answer as not 'YES'"
+fi
+
+
+echo ""
+
+
+# -----
+# - Do some pre-update tasks..
+# -----
+
+echo ""
+echo ""
+echo -e "\033[37m\033[1mDo some pre-update tasks..\033[m"
+echo ""
+
+# - Deaktiviere Cronjobs
+# -
+_backup_crontab_file=/tmp/crontab_root.${backup_date}
+echononl "   Backup Crontab to '$_backup_crontab_file'"
+crontab -l > $_backup_crontab_file 2> $log_file
+if [[ $? -eq 0 ]]; then
+   echo_ok
+else
+   echo_failed
+   fatal "$(cat $log_file)"
+fi
+
+echononl "   Remove crontab for root.."
+crontab -r > $log_file 2>&1
+if [[ $? -eq 0 ]]; then
+   echo_ok
+else
+   echo_failed
+   fatal "$(cat $log_file)"
+fi
+
+
+# - Stop Apache Webserver
+# -
+echo ""
+echononl "   Stop Apache Webserver.."
+if $APACHE2_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl stop apache2
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/apache2 stop
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      fi
+   else
+      echo_skipped
+   fi
+else
+   echo_skipped
+fi
+
+# - Stop Nginx Webservice
+# -
+echo ""
+echononl "   Stop Nginx Webserver.."
+if $NGINX_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl stop nginx
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/nginx stop
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      fi
+   else
+      echo_skipped
+   fi
+fi
+
+echo ""
+
+# - Backup Database
+# -
+echononl "   Backup MySQL database '$DATABASE_NAME'.."
+if [[ "$DATABASE_TYPE" = 'mysql' ]]; then
+   mysqldump $MYSQL_CREDENTIALS --max_allowed_packet=128M --single-transaction $DATABASE_NAME > \
+      ${WEB_BASE_DIR}/${DATABASE_NAME}-v${CURRENT_VERSION}.${backup_date}.sql 2> $log_file
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+
+      blank_line
+      echo -e "\t[ \033[33m\033[1mCommand\033[m ]: \033[37m\033[1mmysqldump $MYSQL_CREDENTIALS \\
+\t                --max_allowed_packet=128M --single-transaction $DATABASE_NAME > \\
+\t                ${WEB_BASE_DIR}/${DATABASE_NAME}-v${PRIOR_VERSION}.${backup_date}.sql\033[m"
+
+      error "$(cat $log_file)"
+
+      echononl "continue anyway [yes/no]: "
+      read OK
+      OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+      while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+         echononl "Wrong entry! - repeat [yes/no]: "
+         read OK
+      done
+      [[ $OK = "yes" ]] || fatal "Abbruch durch User"
+      blank_line
+
+   fi
+elif [[ "$DATABASE_TYPE" = 'postgres' ]]; then
+   PGPASSWORD=$PSQL_PASS \
+   pg_dump $DATABASE_NAME -h $PSQL_SERVER -U $PSQL_USER  \
+      -f ${WEB_BASE_DIR}/${DATABASE_NAME}-v${CURRENT_VERSION}.${backup_date}.sql 2> $log_file
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      fatal "$(cat $log_file)"
+   fi
+fi
+
+echo
+
+
+# -----
+# - Main part of the script
+# -----
+
+echo ""
+echo ""
+echo -e "\033[37m\033[1mMain part of the script\033[m"
+echo ""
+
+
+echononl "   Check if app_api has registered apps .."
+EX_APPS_COUNT=$(
+  sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ app_api:app:list 2>/dev/null \
+    | grep -v "No registered apps" \
+    | grep -E '^[[:space:]]*[a-zA-Z0-9_-]+[[:space:]]' \
+    | wc -l
+)
+
+DAEMONS_COUNT=$(
+  sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ app_api:daemon:list 2>/dev/null \
+    | grep -v "No registered daemon configs" \
+    | grep -E '^[[:space:]]*[a-zA-Z0-9_-]+[[:space:]]' \
+    | wc -l
+)
+echo_done
+
+
+echononl "   Disable 'app_api'.."
+if [ "${EX_APPS_COUNT}" -eq 0 ] && [ "${DAEMONS_COUNT}" -eq 0 ]; then
+
+   sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ app:disable app_api > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      fatal "$(cat $log_file)"
+   fi
+else
+   echo_skipped
+fi
+
+
+
+
+# -----
+# - Doing some post-update tasks
+# -----
+
+echo ""
+echo ""
+echo -e "\033[37m\033[1mDoing some post-update tasks..\033[m"
+
+echo ""
+echononl "   Restart PHP engine.."
+if [[ "$PHP_ENGINE" = "FPM" ]]; then
+   if $SYSTEMD_EXISTS ; then
+      systemctl restart php-${PHP_VERSION}-fpm > $log_file 2>&1
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+			error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+   		[[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+   else
+      /etc/init.d/php-${PHP_VERSION}-fpm restart > $log_file 2>&1
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+			error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+   		[[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+   fi
+else
+   echo_skipped
+fi
+
+# - Start Apache Webserver
+# -
+echo ""
+echononl "   Start Apache Webserver.."
+if $APACHE2_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl start apache2 > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/apache2 start > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+         fi
+      fi
+   else
+      echo_skipped
+      warn "The webserver was not running, so it will be keept down!"
+   fi
+else
+   echo_skipped
+fi
+
+
+# - Start NGINX Webservise
+# -
+echo ""
+echononl "   Start Nginx Webserver.."
+if $NGINX_IS_ENABLED ; then
+   if $IS_HTTPD_RUNNING ; then
+      if $SYSTEMD_EXISTS ; then
+         systemctl start nginx > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+
+         fi
+      else
+         /etc/init.d/nginx start > $log_file 2>&1
+         if [[ $? -eq 0 ]]; then
+            echo_ok
+         else
+            echo_failed
+            error "$(cat $log_file)"
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Interrupted by user."
+         fi
+      fi
+   else
+      echo_skipped
+      warn "The NGINX is not configured as active - so nothing to do."
+   fi
+else
+   echo_skipped
+fi
+
+_redis_cli_bin="$(which redis-cli)"
+if [[ -z "$_redis_cli_bin" ]]; then
+   if [[ -x "/usr/local/bin/redis-cli" ]]; then
+      _redis_cli_bin="/usr/local/bin/redis-cli"
+   fi
+fi
+
+
+echononl "   Flush redis cache.."
+if [[ -x "$_redis_cli_bin" ]]; then
+   $_redis_cli_bin flushall > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      error "$(cat $log_file)"
+   fi
+else
+   echo_skipped
+fi
+
+
+echononl "   Restart redis server.."
+if $SYSTEMD_EXISTS ; then
+   systemctl restart redis-server > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      error "$(cat $log_file)"
+   fi
+else
+   /etc/init.d/redis-server restart  > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      error "$(cat $log_file)"
+   fi
+fi
+
+blank_line
+clean_up 0
diff --git a/restore_nextcloud.sh b/restore_nextcloud.sh
index 21226ae..c58b058 100755
--- a/restore_nextcloud.sh
+++ b/restore_nextcloud.sh
@@ -609,7 +609,6 @@ if [[ "$DATABASE_TYPE" = 'mysql' ]]; then
          mysql $MYSQL_CREDENTIALS $DATABASE_NAME -N -s -e "DROP TABLE \`$_table\`" >> $log_file 2>&1
          if [[ $? -ne 0 ]] ; then
             _failed=true
-            _tables_not_deleted+=("$_table")
          fi
       done
       if $_failed ; then
@@ -617,30 +616,50 @@ if [[ "$DATABASE_TYPE" = 'mysql' ]]; then
          echo_failed
          error "\n\n$(cat $log_file)"
 
-         if [[ ${#_tables_not_deleted[@]} -gt 0 ]] ; then
-            echo ""
-            echo "Tables NOT deleted:"
-            for _table in "${_tables_not_deleted[@]}" ; do
-               echo  "   $_table"
-            done
-            echo ""
-         fi
-
-
-         echononl "continue anyway [yes/no]: "
-         read OK
-         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
-         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
-            echononl "Wrong entry! - repeat [yes/no]: "
-            read OK
+         _tables_not_deleted=()
+         _failed=false
+	      _TABLES="$(mysql $MYSQL_CREDENTIALS $DATABASE_NAME -N -s -e "show tables" 2> $log_file)"
+         echononl "   Try again dropping tables from database '$DATABASE_NAME' .."
+         for _table in $_TABLES ; do
+            mysql $MYSQL_CREDENTIALS $DATABASE_NAME -N -s -e "DROP TABLE \`$_table\`" >> $log_file 2>&1
+            if [[ $? -ne 0 ]] ; then
+               _failed=true
+               _tables_not_deleted+=("$_table")
+            fi
          done
-         [[ $OK = "yes" ]] || fatal "Abbruch durch User"
-         blank_line
+         if $_failed ; then
+
+            echo_failed
+            error "\n\n$(cat $log_file)"
+
+            if [[ ${#_tables_not_deleted[@]} -gt 0 ]] ; then
+               echo ""
+               echo "Tables NOT deleted:"
+               for _table in "${_tables_not_deleted[@]}" ; do
+                  echo  "   $_table"
+               done
+               echo ""
+            fi
+
+
+            echononl "continue anyway [yes/no]: "
+            read OK
+            OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+            while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+               echononl "Wrong entry! - repeat [yes/no]: "
+               read OK
+            done
+            [[ $OK = "yes" ]] || fatal "Abbruch durch User"
+            blank_line
 
          else
             echo_ok
          fi
 
+      else
+         echo_ok
+      fi
+
    fi
 
 fi
diff --git a/update_nextcloud.sh b/update_nextcloud.sh
index 0411e85..7b2359e 100755
--- a/update_nextcloud.sh
+++ b/update_nextcloud.sh
@@ -192,17 +192,87 @@ blank_line() {
    fi
 }
 
+ensure_nc_app() {
+
+   local APP_ID="$1"
+
+   echononl "   Install nextcloud app '$APP_ID'.."
+
+   # 1. Prüfen, ob die App überhaupt installiert ist
+   #
+   # ${OCC_CMD[@]} expandiert jedes Element des Arrays als eigenes Argument.
+   #
+   if ! "${OCC_CMD[@]}" app:list 2>/dev/null | grep -q " - ${APP_ID}:"; then
+
+      "${OCC_CMD[@]}" app:install "$APP_ID" > $log_file 2>&1
+
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+
+         echo -e "\ncommand was: ${OCC_CMD[@]} app:install \"${APP_ID}\""
+
+         error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+         [[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+
+   else
+      echo_skipped
+   fi
+
+   echononl "   Enable App  '${APP_ID}'.."
+   # 2. Prüfen, ob die App aktiviert ist (nur 'Enabled'-Block betrachten)
+   local ENABLED_BLOCK
+   ENABLED_BLOCK="$("${OCC_CMD[@]}" app:list 2>/dev/null \
+      | awk 'BEGIN{flag=0} /Enabled:/ {flag=1; next} /Disabled:/ {flag=0} flag')"
+
+   if echo "$ENABLED_BLOCK" | grep -q " - ${APP_ID}:"; then
+      echo_skipped
+   else
+      "${OCC_CMD[@]}" app:enable "${APP_ID}" > $log_file 2>&1
+
+      if [[ $? -eq 0 ]]; then
+         echo_ok
+      else
+         echo_failed
+
+         echo -e "\ncommand was: ${OCC_CMD[@]} app:install \"${APP_ID}\""
+
+         error "$(cat $log_file)"
+
+         echononl "continue anyway [yes/no]: "
+         read OK
+         OK="$(echo "$OK" | tr '[:upper:]' '[:lower:]')"
+         while [[ "$OK" != "yes" ]] && [[  "$OK" != "no" ]] ; do
+            echononl "Wrong entry! - repeat [yes/no]: "
+            read OK
+         done
+         [[ $OK = "yes" ]] || fatal "Interrupted by user."
+      fi
+
+   fi
+
+}
 
 
 # ----------
-# - Jobhandling 
+# - Jobhandling
 # ----------
 
 # - Run 'clean_up' for signals SIGHUP SIGINT SIGTERM
 # -
 trap clean_up SIGHUP SIGINT SIGTERM
 
-## - 
+## -
 while IFS='' read -r -d '' _conf_file ; do
    source $_conf_file
    if [[ -n "$WEBSITE" ]] ; then
@@ -226,7 +296,7 @@ IFS=$CUR_IFS
 
 
 # =============
-# --- Some 
+# --- Some
 # =============
 
 # - Support systemd ?
@@ -363,6 +433,10 @@ if [[ ! -d ${WEB_BASE_DIR} ]] ; then
    fatal "Web base directory not found (parameter 'WEB_BASE_DIR')"
 fi
 
+if [[ -z "${EXTRA_APPS}" ]]; then
+   fatal "No list of extra apps (parameter EXTRA_APPS) found!"
+fi
+
 [[ -n "$PHP_ENGINE" ]] || PHP_ENGINE=$DEFAULT_PHP_ENGINE
 
 if [[ "$DATABASE_TYPE" != "postgres" ]] && [[ "$DATABASE_TYPE" != "mysql" ]]; then
@@ -413,6 +487,18 @@ DATA_DIR="$(realpath "${WEB_BASE_DIR}/data")"
 OLD_DATA_DIR="$(dirname "${DATA_DIR}")/data-${PRIOR_VERSION}.${backup_date}"
 
 
+# OCC_CMD Kommando als Array definieren.
+#
+# Ausführen des Kommandos:
+#
+#  ${OCC_CMD[@]} 
+#
+# ${OCC_CMD[@]} ist die einzig sichere Art, ein Array als Kommando aufzurufen.  Jedes Element 
+# des Arrays als eigenes Argument.
+#
+OCC_CMD=(sudo -u "$HTTP_USER" "$PHP_BIN" -f "$INSTALL_DIR/occ")
+
+
 
 
 #_CURRENT_DATA_DIR="$(grep datadirectory "${CURRENT_INSTALL_DIR}/config/config.php" 2> /dev/null \
@@ -451,7 +537,7 @@ echo ""
 echo -e   "   Databse name.........................: $DATABASE_NAME"
 echo -e   "   Database type........................: $DATABASE_TYPE"
 #echo ""
-#echo -e   "   Install ColaboraOnline App...........: $INSTALL_COLABORA_ONLINE_APP"   
+#echo -e   "   Install ColaboraOnline App...........: $INSTALL_COLABORA_ONLINE_APP"
 echo ""
 if [[ "$DATABASE_TYPE" = "mysql" ]] ; then
    echo -e   "   Mysql Credentials....................: $MYSQL_CREDENTIALS"
@@ -460,7 +546,7 @@ echo ""
 
 if [[ "$VERSION" = "$PRIOR_VERSION" ]] ; then
    warn "The new version (\033[1m${VERSION}\033[m) is the same as the current version (\033[1m${PRIOR_VERSION}\033[m).
-   
+
                      \033[1mYou have to reinstall some apps manually!\033[m"
 fi
 
@@ -821,8 +907,8 @@ else
    [[ $OK = "yes" ]] || fatal "Interrupted by user."
 fi
 
-# - Synchronisiere neues Installationsverzeichnis mit 
-# - den extrahierten Dateien 
+# - Synchronisiere neues Installationsverzeichnis mit
+# - den extrahierten Dateien
 # -
 echononl "   Sync downloaded (new) nextlcoud int '${INSTALL_DIR}'.."
 rsync -a ${SRC_BASE_DIR}/nextcloud/ ${INSTALL_DIR}/ > $log_file 2>&1
@@ -941,7 +1027,7 @@ blank_line
 # -
 echo ""
 echo -e "   Update Nextcloud\n"
-su -c"${PHP_BIN} ${WEB_BASE_DIR}/htdocs/occ upgrade" -s /bin/bash $HTTP_USER 
+su -c"${PHP_BIN} ${WEB_BASE_DIR}/htdocs/occ upgrade" -s /bin/bash $HTTP_USER
 echo ""
 if [[ $? -eq 0 ]]; then
    info "Updating nextcloud core was successfully.."
@@ -1012,7 +1098,7 @@ if $(systemctl list-units --full -all | grep -Fq "notify_push") ; then
 
    fi
 
-   echononl "   Enable Nextcloud App 'notify_pushi'.."
+   echononl "   Enable Nextcloud App 'notify_push'.."
    if $(
          sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ app:list --enabled \
          | grep -q notify
@@ -1030,7 +1116,7 @@ if $(systemctl list-units --full -all | grep -Fq "notify_push") ; then
    fi
 
 
-   echononl "   Setup Nextcloud App 'notify_pushi'.."
+   echononl "   Setup Nextcloud App 'notify_push'.."
    script -q -c "sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ notify_push:setup" /dev/null <<< $'\n' \
       > $log_file 2>&1
    if [[ $? -eq 0 ]]; then
@@ -1040,10 +1126,22 @@ if $(systemctl list-units --full -all | grep -Fq "notify_push") ; then
       fatal "$(cat $log_file)"
    fi
 
+   blank_line
+
 fi
 
-#
-#
+
+# -----
+# - Reinstall estra apps
+# -----
+
+declare -i index=1
+for APP in "${EXTRA_APPS[@]}"; do
+   [[ ${index} -gt 1 ]] && blank_line
+  ensure_nc_app "$APP"
+  (( index++ ))
+done
+
 ## - Install and enable nextcloud app 'calendar'
 ## -
 #_app="calendar"
@@ -1420,6 +1518,39 @@ echo ""
 echo -e "\033[37m\033[1mDoing some post-update tasks..\033[m"
 echo ""
 
+echononl "   Check if app_api has registered apps .."
+EX_APPS_COUNT=$(
+  sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ app_api:app:list 2>/dev/null \
+    | grep -v "No registered apps" \
+    | grep -E '^[[:space:]]*[a-zA-Z0-9_-]+[[:space:]]' \
+    | wc -l
+)
+
+DAEMONS_COUNT=$(
+  sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ app_api:daemon:list 2>/dev/null \
+    | grep -v "No registered daemon configs" \
+    | grep -E '^[[:space:]]*[a-zA-Z0-9_-]+[[:space:]]' \
+    | wc -l
+)
+echo_done
+
+
+echononl "   Disable 'app_api'.."
+if [ "${EX_APPS_COUNT}" -eq 0 ] && [ "${DAEMONS_COUNT}" -eq 0 ]; then
+
+   sudo -u "${HTTP_USER}" ${PHP_BIN} -f /${WEB_BASE_DIR}/htdocs/occ app:disable app_api > $log_file 2>&1
+   if [[ $? -eq 0 ]]; then
+      echo_ok
+   else
+      echo_failed
+      fatal "$(cat $log_file)"
+   fi
+else
+   echo_skipped
+fi
+
+
+
 # - Add missing columns
 # -
 echononl "   Add missing columns .."