Can't connect to database after upgrade

[Transistor]

Version: roundcubemail-1.4.7-complete.tar.gz

• I backed up my old email installation.
• I've uploaded the gz file and unzipped it via cPanel on my host.
• I've edited the /config/config.inc.php and entered the $config['db_dsnw'] setting and the $config['des_key'] so the username and database settings should be correct.

The installer is giving me this error:

Code Select Expand

NOT OK(SQLSTATE[HY000] [2054] The server requested authentication method unknown to the client)

and if I go to the normal email site login page I get:

Code Select Expand

DATABASE ERROR: CONNECTION FAILED!
Unable to connect to the database!
Please contact your server-administrator.

I'm a bit stuck at this point. Can anyone give me some things to try?

[JohnDoh]

You had a previous version of Roundcube running? Did you upgrade anything else on your server, like have you upgraded your database server? Roundcube has used PDO for database access since version 0.9 so unless you were running a really old version before how Roundcube access the database has not changed.