“An active PHP session was detected” warning

The site health tool of WordPress reports the warning “An active PHP session was detected”. To fix this issue the file montapacking-checkout.php at line 172 needs to be changed from:

function montacheckout_register_session()
{
    if (!session_id()) {
        session_start();
    }
}

to:

function montacheckout_register_session()
{
    if (!session_id()) {
        session_start( [
            'read_and_close' => true,
        ] );
    }
}