Starting from Laravel 5.2, as stated in documentation (https://laravel.com/docs/5.2/upgrade#upgrade-5.2.0):
Caching And Env
If you are using the config:cache command during deployment, you must make sure that you are only calling the env function from within your configuration files, and not from anywhere else in your application.
If you are calling env from within your application, it is strongly recommended you add proper configuration values to your configuration files and call env from that location instead, allowing you to convert your env calls to config calls.
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