##Open terminal in container
docker exec -it nextcloud bash

##Turn on maintenance mode
sudo -u abc php7 /config/www/nextcloud/occ maintenance:mode --on

##Backup current nextcloud install
mv /config/www/nextcloud /config/www/nextcloud-backup

##Grab newest nextcloud release and unpack it
wget https://download.nextcloud.com/server/releases/latest.tar.bz2
tar -xvf latest.tar.bz2 -C /config/www

##Copy across old config.php from backup
cp /config/www/nextcloud-backup/config/config.php /config/www/nextcloud/config/config.php

##Now Restart docker container
exit
docker restart nextcloud

##Open terminal in container
docker exec -it nextcloud bash

##Perform upgrade
sudo -u abc php7 /config/www/nextcloud/occ upgrade

##Turn off maintenance mode
sudo -u abc php7 /config/www/nextcloud/occ maintenance:mode --off

## Now Restart docker container
exit
docker restart nextcloud

Login to the console of the docker host and execute:

docker exec -it <docker name> updater.phar

Edit the file /config/nginx/site-confs/default.conf and comment out the IPv6 listeners.

'trusted_proxies' =>
array (
  0 => 'xxx.xxx.xxx.xxx',
),
'enabledPreviewProviders' =>
array (
  0 => 'OC\\Preview\\BMP',
  1 => 'OC\\Preview\\GIF',
  2 => 'OC\\Preview\\JPEG',
  3 => 'OC\\Preview\\Krita',
  4 => 'OC\\Preview\\MarkDown',
  5 => 'OC\\Preview\\MP3',
  6 => 'OC\\Preview\\OpenDocument',
  7 => 'OC\\Preview\\PNG',
  8 => 'OC\\Preview\\TXT',
  9 => 'OC\\Preview\\XBitmap',
  10 => 'OC\\Preview\\Movie',
'maintenance_window_start' => 1,
'default_phone_region' => 'US',
'skeletondirectory' => '',

• Update /config/nginx/nginx.conf – make sure ‘client_max_body_size’ equals 0 (zero).
• Update /config/nginx/site-confs/default.conf – make sure ‘client_max_body_size’ equals 16G.