Drupal 8.x

I want to update Drupal from 8.8.4 to 8.9.0. However, when I run

composer update drupal/core --with-dependencies

I get this error:

> DrupalProject\composer\ScriptHandler::checkComposerVersion
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

Hello,

I followed the instructions in order to migrate to Drupal 9 from Drupal 8 but the "composer update" command returns some errors.

https://www.drupal.org/docs/upgrading-drupal/upgrading-from-drupal-8-to-drupal-9-or-higher

Here is my composer.json file:

Hello,

I followed the instructions in order to migrate to Drupal 9 from Drupal 8 but the "composer update" command returns errors.

https://www.drupal.org/docs/upgrading-drupal/upgrading-from-drupal-8-to-drupal-9-or-higher

Here is my composer.json file:

Hello,

I followed the instructions in order to migrate to Drupal 9 from Drupal 8 but the "composer update" command returns errors.

https://www.drupal.org/docs/upgrading-drupal/upgrading-from-drupal-8-to-drupal-9-or-higher

Here is my composer.json file:

Hello,

I followed the instructions in order to migrate to Drupal 9 from Drupal 8 but the "composer update" command returns errors.

https://www.drupal.org/docs/upgrading-drupal/upgrading-from-drupal-8-to-drupal-9-or-higher

Here is my composer.json file:

Hi

I am looking for a custom theme developer to

help me setup a site with fields customisation, views theming, node field settings, upgrade to D9, etc.

Please feel free to send me message here. let us discuss and finale a timeline and price.