Laravel Spark, the commercial Laravel package that provides instant scaffolding for subscription billing, has just released v2.
The 2.0 release is a free upgrade for all license holders and it adds compatibility with Laravel 5.3 as well as deprecating the Spark installer in favor of using Composer directly.
The upgrade guide says you should review the entire Laravel 5.3 upgrade guide and make any changes to your application to reflect those changes. After that, there are no further code upgrades you need to make before using Spark 2.0.
Once you have completed applying the changes listed in the Laravel 5.3 upgrade guide, you are ready to upgrade your underlying Spark dependency.