title: How to replace/remove 4(+)-byte characters from a UTF-8 string in PHP?
body: <p>It seems like MySQL <a href="http://dev.mysql.com/doc/refman/5.5/en/charset-unicode-utf8mb4.html" rel="noreferrer">does not support</a> characters with more than 3 bytes in its default UTF-8 charset.</p>
  
  <p>So, in PHP, how can I get rid of all 4(-and-more)-byte characters in a string and replace them with something like by some other character?</p>