Upgrading a system is always fun and full of headaches, my last one was with the new mysqlnd extension from php 5.3. I cannot manage to connect to mysql from symfony.
I always get:
SQLSTATE[HY000]  mysqlnd cannot connect to MySQL 4.1+ using old authentication
After struggling a while on google, I cannot find any solution. So I went back to the RTFM idiomatic expression.
It is what I found:
So the problem was easy to solve, just reset the user's password.
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('mypassword');