Configuring Modes

Now that configureMode is gone from slim v3, how do you recommend we customize configuration settings for different modes, dev, production, etc?

I guess it depends on how extensive your config changes are. Assuming you want to just change a few things like DB connection info, I would do the following (if someone knows a better way, please tell me as well):

At the start of settings.php, place a single variable like this:

$production = false; // or true, whatever you need

Then in your settings do the following:

'database' => [
        'driver'    => 'mysql',
        'host'      => 'localhost',
        'database'  => $production ? "DBName_A" : "DBName_B",
        'username'  => $production ? "DBUser_A" : "DBUser_B",
        'password'  => $production ? "DBPass_A" : "DBPass_B";,
        'charset'   => 'utf8',
        'collation' => 'utf8_unicode_ci',
        'prefix'    => '',

etc. Quite easy and manageable IMHO.