EllisLab/CodeIgniter — pull request #2610 by mjnaderi (2013-08-22 08:54:04+00:00)
Title: character_limiter now works correct for UTF-8 strings

strlen() doesn't return the actual length for unicode strings. For example strlen('سلام') returns 8, but length of سلام is 4. strlen(utf8_decode('سلام')) returns correct value 4.
Reference: http://www.php.net/manual/de/function.strlen.php#45407