Upgrading Drupal

Hello, 

my javascript code (ezs3 videoplayer) do not work in Drupal 9. I use it for many years in Drupal 6 and late drupal 7 without problems, but in Drupal 9 this code do not work. I use over 1000 Videos, every with another javascript code for every single video in 1000 drupal pages in Drupal 7. Now I will upgrade to Drupal 9 and no video is playing. I only see the code like this example on a page:

Hi, I tried exporting my data from Drupal 7 without being programmer, and without using Migrate. For me that is still complicated..

This is how I exported my data out of Drupal 7. The question is, how to get it into Drupal 10?

1)       Nodes through Export views; https://www.drupal.org/project/vbo_export necessary modules: Views Bulk Operations, Entity API (ingeschakeld), Views, Chaos tools, File, Field, Field SQL storage, Libraries, System.

Hi, I ran composer to update my core installation to 9.4.5 and since then, the database update fails with a message of an out of date libmysqlclient driver, v. 3.1.20 while 5.5.3 is the minimum. The error message is in french but is pretty straight forward:

I'm just starting out looking at Drupal configuration management and I'm wondering if I can manage CLI imports and exports from the files using composer. I'm also wondering if it's best practice to use drush or composer in general in Drupal 10. I get the impression that drush was the best method but composer is becoming the norm. Also what versions for Drupal 8, 9, and 10? I'd love to hear you perspectives so I can build the best way. 

I apologize if this isn't the correct place for this, but is anyone else running into this?

PHP Fatal error:  Cannot declare class Dealerdirect\Composer\Plugin\Installers\PHPCodeSniffer\Plugin, because the name is already in use in /vendor/dealerdirect/phpcodesniffer-composer-installer/src/Plugin.php on line 35

I haven't encountered something like this before.

I already showed the way I acted at the URL below.

https://www.drupal.org/forum/support/upgrading-drupal/2023-02-07/from-a-...

Unfortunately nobody answered so far.

The reason why I suspect there's something wrong in what I did is described at the URL below (403 for files in sites/default/files).