Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires roave/better-reflection ^6.41.0 -> satisfiable by roave/better-reflection[6.41.0]. - roave/better-reflection 6.41.0 requires nikic/php-parser ^5.1.0 -> found nikic/php-parser[v5.1.0] but it conflicts with your root composer.json require (^4.19.1). Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.