Upgrading Drupal

I have drupal multisite whitch I want to update from version 7.89 to 7.91, but when I copy new files, got blank page. It's the same with version 7.90. Data is stored in postgree data base 9.5.23 version. Site is runing on php 7.0. There is one database for all sites, and each site has it's own scheme. 

I was thinking mybe i have to clear cache, so i open update.php, and it shows this error:

Hello,

I'm trying to Upgrade my goalgorilla/open_social Version 10.3.8 to 11.0.0 by using the following command:

composer require 'goalgorilla/open_social:11.0.0' -W --dry-run

But always running into this error:

I'm using a Bitnami package to develop a local site, and my development instance is running 9.3.12. I want to upgrade it and can't figure out how.

Hello and good morning.

I'm updating core to my drupal site to 8.9.20 previous to upgrade to drupal9; in this version it was working on php 7.0; my server was updated on php 7.3 and the drupal site crashed showing the next test: "The website encountered an unexpected error. Please try again later." ; once i return to php7.0 works again; but i need php7.3; what can i do for my site works propertly on php7.3?

Thanks for your help.

composer update does not find this. nor does

composer update "drupal/core-*" --with-all-dependencies

Manual updates required

Automatic updates of Drupal core are not supported at this time.