core update with composer

composer outdated shows the newest available version, not just the next minor update. To which version you will update when running composer update then depends on the constraints you set in your composer.json – I assume something like ^10.0 should be there, limiting updates to minor versions of Drupal 10. Once you updated to the latest version of Drupal 10 (and ran all necessary database updates) you might consider changing the version constraint to ^11.0 to upgrade to Drupal 11.

The prohibits subcommand answers this.

in my composer.jason

"drupal/core-composer-scaffold": "^10.3",
"drupal/core-project-message": "^10.3",
"drupal/core-recommended": "^10.3",

See #4. The prohibits subcommand will explain exactly why.