How can I determine if data consists of valid utf-8 characters?

As of version 4.1.6 and later, the isutf8() function can be used for determining if string consist of valid UTF-8 characters. This function tests whether a string is a valid UTF-8 string. Returns true if the string conforms to UTF-8 standards, and false otherwise. Best practice is to avoid loading non UTF-8 data into the database.