Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires nextcloud/ocp dev-master -> satisfiable by nextcloud/ocp[dev-master]. - nextcloud/ocp dev-master requires psr/container ^2.0.2 -> found psr/container[2.0.2] but the package is fixed to 1.1.1 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command. Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.