Your requirements could not be resolved to an installable set of packages. Problem 1 - Conclusion: don't install laminas/laminas-mvc 3.6.0 (conflict analysis result) - Conclusion: don't install laminas/laminas-mvc 3.6.1 (conflict analysis result) - Conclusion: don't install laminas/laminas-mvc 3.7.0 (conflict analysis result) - Root composer.json requires laminas/laminas-serializer ^3.0.0 -> satisfiable by laminas/laminas-serializer[3.0.0]. - Root composer.json requires laminas/laminas-mvc ^3.3.0 -> satisfiable by laminas/laminas-mvc[3.3.0, ..., 3.7.0]. - laminas/laminas-mvc[3.3.0, ..., 3.3.5] require laminas/laminas-servicemanager ^3.7 -> satisfiable by laminas/laminas-servicemanager[3.7.0, ..., 3.22.1]. - You can only install one version of a package, so only one of these can be installed: laminas/laminas-servicemanager[3.0.3, ..., 3.22.1, 4.1.0, 4.2.0]. - laminas/laminas-serializer 3.0.0 requires laminas/laminas-servicemanager ^4.1 -> satisfiable by laminas/laminas-servicemanager[4.1.0, 4.2.0]. - Conclusion: don't install laminas/laminas-servicemanager 4.2.0 (conflict analysis result) Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.