PHP UTF8 - ISO-8859-1 encoding
===

I am working on my first PHP code and i want to display some email subjects.
    
    ...
    $header = imap_headerinfo($imap, $i);
    $raw_body = imap_body($imap, $i);
    $subject =  utf8_encode($header->subject);

    echo $subject;
    echo "<br>";
    ...

But for the Subject "ää üü öö ß" the output looks like that:

=?ISO-8859-1?B?5OQg/Pwg9vYg3w==?=

regards