composer require backpack/base:"^0.8.0"
composer require backpack/crud:"^3.3.0"
composer require livecontrol/eloquent-datatable
执行之后，确认版本号已经升级
composer show backpack/crud
name : backpack/crud
descrip. : Quickly build an admin interface for your Eloquent models, using Laravel 5. Build a CMS in a matter of minutes.
keywords : Admin Interface, Content management system, admin panel, cms, content management framework, create, crud, delete, read, update
versions : * 3.3.17
参考
https://laravel-backpack.readme.io/v3.3/docs/upgrading-crud-32-to-33