Can not set custom title on some WordPress setups

Question

I'm having a bit of an issue changing the title on a custom page. Most the time the standard code works, but for whatever reason on certain WordPress setups I am unable to change the default title.

What usually works, but is not working in this situation:

function customtitle(){
    return "custom title";
}
add_filter('wp_title', 'customtitle', 10);

I'm also aware of the issues with changing custom titles and the yoast plugin. On the current WordPress setup I'm working with yoast is not installed. I wanted to know if there was another hook or method that I can override the title over the current default title.

Answer 1

This is most likely due to difference in your theme's support. Some themes render the title by using the wp_title filter, some by using pre_get_document_title. If your theme has this line in its functions.php file:

add_theme_support('title-tag');

Then you need to use the pre_get_document_title filter, as follows:

add_filter('pre_get_document_title', 'my_title');
function my_title() {
    return 'Some title';
}

This is for the newer versions of WordPress. The old installations might be still using the legacy wp_title() function, which you already mentioned in your question.