Nagios MySQL Replication Plugin Fails with UNKNOWN: Should Never Reach This Part

I got the following Nagios error after setting up replication between two MySQL 5.6 servers and monitioring the slave.

"UNKNOWN: should never reach this part"

nagios_mysql

This plugin was preivously working on MySQL 5.5 servers.

It appears that the MySQL 5.6 replication has a different output from MySQL 5.5. Therefore you will need to download the latest copy of check_mysql_slavestatus which fixes this issue.