Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires jwage/changelog-generator ^1.4.0 -> satisfiable by jwage/changelog-generator[1.4.0]. - jwage/changelog-generator 1.4.0 requires psr/http-message ^1.0.1 -> found psr/http-message[1.0.1, 1.1] but it conflicts with your root composer.json require (^2.0). Problem 2 - Root composer.json requires laminas/laminas-diactoros ^2.26.0 -> satisfiable by laminas/laminas-diactoros[2.26.0]. - laminas/laminas-diactoros 2.26.0 requires psr/http-message ^1.1 -> found psr/http-message[1.1] but it conflicts with your root composer.json require (^2.0). Problem 3 - laminas/laminas-diactoros 2.26.0 requires psr/http-message ^1.1 -> found psr/http-message[1.1] but it conflicts with your root composer.json require (^2.0). - phly/keep-a-changelog 2.12.1 requires laminas/laminas-diactoros ^2.4.1 -> satisfiable by laminas/laminas-diactoros[2.26.0]. - Root composer.json requires phly/keep-a-changelog ^2.12.1 -> satisfiable by phly/keep-a-changelog[2.12.1]. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.