Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires ghostwriter/testify ^1.0 || dev-main as 0.999 -> satisfiable by ghostwriter/testify[dev-main]. - ghostwriter/testify dev-main requires ghostwriter/event-dispatcher ^5.0.0 -> found ghostwriter/event-dispatcher[5.0.0, 5.0.1] but it conflicts with your root composer.json require (^4.0.0). Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.