Your requirements could not be resolved to an installable set of packages. Problem 1 - oat-sa/tao-core dev-feature/adf-1590/optimize-permissions-task-queue requires oat-sa/generis >=15.29 -> satisfiable by oat-sa/generis[v15.29.0, v15.30.0, v15.31.0, 9999999-dev]. - You can only install one version of a package, so only one of these can be installed: oat-sa/generis[dev-feature/adf-1590/optimize-permissions-task-queue, dev-master, v14.0.0, ..., v14.4.0, v15.0.0, ..., v15.31.0]. - oat-sa/extension-tao-dac-simple dev-1576908512e1745e39151ab1e3dd54283f136545 requires oat-sa/generis dev-feature/adf-1590/optimize-permissions-task-queue as 99.99 -> satisfiable by oat-sa/generis[dev-feature/adf-1590/optimize-permissions-task-queue]. - oat-sa/extension-tao-dac-simple dev-1576908512e1745e39151ab1e3dd54283f136545 requires oat-sa/tao-core dev-feature/adf-1590/optimize-permissions-task-queue as 99.99 -> satisfiable by oat-sa/tao-core[dev-feature/adf-1590/optimize-permissions-task-queue]. - Root composer.json requires oat-sa/extension-tao-dac-simple dev-1576908512e1745e39151ab1e3dd54283f136545 as v99.99.99 -> satisfiable by oat-sa/extension-tao-dac-simple[dev-1576908512e1745e39151ab1e3dd54283f136545].