Nextcloud updater not working under ubuntu16.04 with nginx/php7/redis, manual updated shows wrong version

Hi,
I got some trouble with updating my installation.

I am pretty new to nextcloud. I installed it on my home server and everything is working as i expected it.
I am used to use nginx because I am not a huge fan of Apaches HTTPD. The Nextcloud documentation is pretty awesome btw.

A couple of weeks ago I got notified that there is a new version. When I tried to update it via the backend I got the following error.


First I thought the remote server got some issues, but I still get the error now. So I tried to update manually.
I followed the documentation (https://docs.nextcloud.com/server/11/admin_manual/maintenance/manual_upgrade.html) nearly step by step.

I am also used to keep old versions of working software to do a rollback if everything blows up.
So i just symlink stuff.

[12:48:14] root@srv01:[/srv/webapps/nextcloud]: ls -al
drwxr-xr-x 1 www-data www-data 3002 Mai  8 06:25 logs
lrwxrwxrwx 1 root     root       15 Mai  8 12:06 public -> releases/11.0.3
drwxr-xr-x 1 www-data www-data   24 Apr 28 13:02 releases
drwxr-xr-x 1 www-data www-data   54 Mai  8 12:08 shared

[12:48:29] root@srv01:[/srv/webapps/nextcloud]: ls -al releases/
drwxr-xr-x 1 www-data www-data 448 Mär 13 10:55 11.0.2
drwxr-xr-x 1 www-data www-data 414 Apr 28 13:03 11.0.3

[12:48:53] root@srv01:[/srv/webapps/nextcloud]: ls -al releases/11.0.3/config/
lrwxrwxrwx 1 www-data www-data    26 Mai  8 12:03 config.php -> ../../../shared/config.php
-rw-r--r-- 1 www-data www-data 41688 Apr 22 06:27 config.sample.php
-rw-r--r-- 1 www-data www-data   225 Apr 22 06:27 .htaccess

[12:49:08] root@srv01:[/srv/webapps/nextcloud]: ls -al shared
drwxr-xr-x 1 www-data www-data   50 Apr 28 13:07 3rdparty_apps
-rw-r----- 1 www-data www-data 1161 Mai  8 12:10 config.php
drwxrwx--- 1 www-data www-data  308 Apr 28 12:43 data

Here is my config.php

<?php
$CONFIG = array (
  'instanceid' => 'random',
  'passwordsalt' => 'morerandom',
  'secret' => 'verymorerandom',
  'trusted_domains' =>
  array (
    0 => 'nextcloud.tld',
  ),
  'datadirectory' => '/srv/webapps/nextcloud/shared/data',
  'overwrite.cli.url' => 'https://nextcloud.tld',
  'dbtype' => 'mysql',
  'version' => '11.0.3.2',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'nextcloud.tld',
  'dbpassword' => 'verystrongasecretpassword;-)',
  'logtimezone' => 'UTC',
  'installed' => true,
  'memcache.local' => '\\OC\\Memcache\\Redis',
  'memcache.locking' => '\\OC\\Memcache\\Redis',
  'redis' =>
  array (
    'host' => '/var/run/redis/redis.sock',
    'port' => 0,
  ),
  'mail_smtpmode' => 'php',
  'mail_from_address' => 'FROM',
  'mail_domain' => 'nextcloud.tld',
  'mail_smtpauthtype' => 'LOGIN',
  'log_type' => 'owncloud',
  'loglevel' => 2,
  'singleuser' => false,
  'maintenance' => false,
  'updater.secret' => 'randommcrandomness',
);

So, everything is nice set up and the update went through:

[12:06:53] root@srv01:[/srv/webapps/nextcloud/public]: sudo -u www-data php occ upgrade
Nextcloud or one of the apps require upgrade - only a limited number of commands are available
You may use your browser or the occ upgrade command to do the upgrade
Set log level to debug
Updating database schema
Updated database
Disabled 3rd-party app: direct_menu
Disabled 3rd-party app: files_markdown
Drop old database tables

 Done
 31/31 [============================] 100%
Remove old (< 9.0) calendar/contact shares
 Done
 4/4 [============================] 100%
Fix permissions so avatars can be stored again
 Done
 2/2 [============================] 100%
Starting code integrity check...
Finished code integrity check
Update successful
Maintenance mode is kept active
Reset log level

But I still have that popup with tells me that my version is old, and even the scan.nextcloud.com shows the old version.
Rating A+
Running Nextcloud 11.0.2.7
Latest patch level
Major version still supported

Any Ideas?
I already restartet the redis-server and the nginx.

Edit:
This is what I get from the Logifle:

==> access.log <==
1.2.3.4 - - [08/May/2017:13:16:05 +0200] "POST /updater/index.php HTTP/1.1" 500 5 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36"