Anyone who has works with XML a lot possibly would have encountered this XML parser error message such as "Invalid byte 2 of 2-byte UTF-8 sequence". The main reason for this error is that, the XML Parser cannot parse the XML since it contains non UTF-8 encoded characters.
The exception stack trace looks some thing like this.
[Fatal Error] :1:25: Invalid byte 1 of 1-byte UTF-8 sequence.