Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires psalm/plugin-phpunit ^0.20.0 -> satisfiable by psalm/plugin-phpunit[0.20.0]. - Root composer.json requires vimeo/psalm ^6 -> satisfiable by vimeo/psalm[6.0.0, ..., 6.16.1]. - psalm/plugin-phpunit 0.20.0 requires psalm/psalm-plugin-api ^0.1 -> satisfiable by psalm/psalm-plugin-api[0.1.0]. - psalm/psalm-plugin-api 0.1.0 conflicts with vimeo/psalm <7.0.0. - vimeo/psalm[6.0.0, ..., 6.5.0] require php ~8.1.17 || ~8.2.4 || ~8.3.0 || ~8.4.0 -> your php version (8.5.0RC1) does not satisfy that requirement. - vimeo/psalm[6.5.1, ..., 6.13.1] require php ~8.1.31 || ~8.2.27 || ~8.3.16 || ~8.4.3 -> your php version (8.5.0RC1) does not satisfy that requirement. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.