How to update shared host installation from 11.0.3

Hello!

I am using Nextcloud on my shared host webspace. I got no access to the server or any console. I tried to update from the webinterface several times. It always ends with having a blank side. I can’t login or do anything after upgrade. So I must copy the original files back and reset the config. The db always seems to be working fine.
It doesn’t matter to me to which version I can update. When I got a way that works, I would do it multiple times.

Nextcloud version (eg, 12.0.2): 11.0.3
Operating system and version (eg, Ubuntu 17.04): unknown
Apache or nginx version (eg, Apache 2.4.25): unknown
PHP version (eg, 7.1): 7.0 (I can upgrade to 7.1)

The issue you are facing:

Is this the first time you’ve seen this error? (Y/N): N

Steps to replicate it:

  1. Using the Updater from the Admin Panel

The output of your Nextcloud log in Admin > Logging:

blank site