It says in the documentation: "Underscores in property names can be problematic when using getters and setters. ... As much of the system expects camel case, and underscores are commonly removed, it is recommended to name your properties in the manner shown throughout the documentation. "
And then we see that Invo is using underscores, as in: public $created_at;
and Vökuró uses camelCase as in: public $createdAt;
What is the correct approach? CamelCase?