Custom Aliases not working I'm trying to setup aliases following the instructions in the docs, but I can't get them to work (for example they don't appear when setting paths for Assets).
I copied and pasted the code exactly as the example in the docs, and the env variable ROOT_URL shows up in the CP, but the alias @rootUrl does not. Is there another step? I tried clearing caches and logging out/in, but that didn't help.
In the config/general.php file I pasted the code last, right below Dev environment settings. Here is that last portion of the config:
    // Dev environment settings
        'dev' =&gt; [
            // existing settings ...
            'backupCommand' =&gt; getenv('BACKUP_COMMAND'),
            'restoreCommand' =&gt; getenv('RESTORE_COMMAND'),
        ],

    // -- config/general.php Code example from docs --
        'aliases' =&gt; [
            '@rootUrl' =&gt; getenv('ROOT_URL'),
        ],
];

Also, the 3.6 upgrade documentation states (emphasis mine):

The siteName and siteUrl config settings have been deprecated. We strongly recommend you set your sites’ names and URLs using environment variables instead.

So, does this mean I shouldn't even be bothering with aliases? Should everything be an environment variable only?
Try to add your alias array within one of your environment array such as:
&lt;?php

return [
    // Global settings
    '*' =&gt; [
        'aliases' =&gt; [
            '@rootUrl' =&gt; getenv('ROOT_URL'),
        ],
    ],

    // Dev environment settings
    'dev' =&gt; [
        // ...
    ],

    // Staging environment settings
    'staging' =&gt; [
        // ...
    ],

    // Production environment settings
    'production' =&gt; [
        // ...
    ],
];