Your requirements could not be resolved to an installable set of packages. Problem 1 - yiisoft/db-sqlite[1.1.0, ..., 1.2.0] require yiisoft/db ^1.2 -> satisfiable by yiisoft/db[1.2.0, 1.3.0]. - yiisoft/db-sqlite[1.0.0, ..., 1.0.1] require yiisoft/db ^1.0 -> satisfiable by yiisoft/db[1.0.0, ..., 1.3.0]. - You can only install one version of a package, so only one of these can be installed: yiisoft/db[dev-master, 1.0.0, ..., 1.3.0]. - yiisoft/active-record dev-master requires yiisoft/db dev-master -> satisfiable by yiisoft/db[dev-master]. - yiisoft/active-record 3.0.x-dev is an alias of yiisoft/active-record dev-master and thus requires it to be installed too. - Root composer.json requires yiisoft/active-record ^3.0@dev -> satisfiable by yiisoft/active-record[3.0.x-dev (alias of dev-master)]. - Root composer.json requires yiisoft/db-sqlite ^1.0 -> satisfiable by yiisoft/db-sqlite[1.0.0, 1.0.1, 1.1.0, 1.2.0].