Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires roave/better-reflection ^6.51.0 -> satisfiable by roave/better-reflection[6.51.0]. - roave/better-reflection 6.51.0 requires nikic/php-parser ^5.4.0 -> found nikic/php-parser[v5.4.0] but it conflicts with your root composer.json require (^4.19.4). Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.