The version of MySQL you are running should already be handling this with the newer files. Since the version is so close though it may indicate that there was not a complete upgrade of the MySQL instance on the server. Do you have root access to the MySQL server? If not you will need to contact your host, I think the easiest thing to do would be to update the password for your user to use the old style password that will be compatible with the files being use by MySQL. In the link I posted there is a query that you can execute if you have root access that will do this update of the password for you. If you don't have root access your hosts admin will need to run this for you. Updating the MySQL files to latest should also do the trick, either way your host should be able to handle this for you.