Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires phpunit/phpunit ^10.0 -> satisfiable by phpunit/phpunit[10.0.0, ..., 10.5.x-dev]. - phpunit/phpunit[10.0.0, ..., 10.5.26] require sebastian/diff ^5.0 -> found sebastian/diff[5.0.0, ..., 5.1.x-dev] but the package is fixed to 6.0.2 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command. - phpunit/phpunit[10.5.27, ..., 10.5.x-dev] require sebastian/diff ^5.1.1 -> found sebastian/diff[5.1.1, 5.1.x-dev] but the package is fixed to 6.0.2 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.