Upgrading Drupal

I am not a tech guy. but I wanted to upgrade from Drupal 8.9 to Drupal 9.36. is there a non-technical way to do so? I can see the composer.json file in the file manager. But apart from that, I am not sure what to do next. Please let me know if there is a non-technical way to upgrade like updating from Drupal 8.7 to 8.9?

www.japanesemarine.com

Thanks and regards

I've been working on my first Drupal 8 to 9 update and have been slowly whittling away on the issues Composer throws at me but I've gotten stuck on this new set. I'm not sure where to update or make changes to resolve the symfony and core-recommended requirements.

These are the errors:

Hi, 

i upgraded a website from Drupal 8.9.* to 9.3.5 checking everything (modules, some edited code etc.) and without errors, everything works fine but i can't see the bartik theme (just text and links).

If i turn off the css aggregation from the options i can see the administration theme and bartik looks better but it is like no images or css.

I tried various solutions found on the net but no hope to see bartik works.

I use Drupal on the hosting altervista.org and i use MySQL 8 and PHP 8.

I'm currently upgrading from 7 to 8.9. I'm pretty far into the migration but I have been noticing administrative buttons don't work. When clicked the "loading watch" will appear for a brief moment then disappear and then nothing else happens. in the developer tools in chrome I get:

"Drupal.AjaxError {message: '\nAn AJAX HTTP error occurred.\nHTTP Result Code: 20…      \\u003C\\/ul\\u003E\\n  \\n\\n","help-main":""}}]', name: 'AjaxError'}"

Hi, 

When I ran composer update drupal/core --with-dependencies to upgrade from Drupal core 9.2.7 to the latest, I got an error when I accessed the Drupal home page. Am I doing the upgrade correctly?

The website encountered an unexpected error. Please try again later.