Drupal 8 Upgrade to 8.5.0 failed

Upgrade from 8.4.5 to 8.5.0 failed

I upgraded my site in the usual manner. done this before with a few 8.x.x versions with success:

removed core and vendor and all files in the main directory

Copied 8.5.0 core and vendor and all files in the main directory to the old 8.4.5 place.

Then tried in the browser to https://xxx.example.com/update.php and get the errror message “The website encountered an unexpected error. Please try again later.”

I am on a hosted server and cannot use composer or drush. What could be wrong?

I tried it twice with the same results. If I’m going back to the 8.4.5 version, it works without any problem

Thanks in advance for any help

Drupal version: 

Source: https://www.drupal.org/taxonomy/term/21/feed