Switching from MySQL to MariaDB

This blog started life on MySQL 4.x & continued to live on 5.0 until today. Whilst performing maintenance, all the packages came up to date apart from two, the MySQL 5.0 client & server which had been long removed.
I was about to commence with installing version 5.5 when I remembered a conversation I had a couple of weeks back about MariaDB, after a quick check to see what the switchover entailed, I decided to install to MariaDB instead.
It’s intended to act as a drop in replacement for MySQL, my instance has been for serving blogs & other fairly common 3rd party open source software so I didn’t have to do much apart from run mysql_upgrade after install.
In /var/db/mysql/server.example.com.err MariaDB logged
Column count of mysql.db is wrong. Expected 22, found 20. Created with MySQL 50084, now running 50312. Please use mysql_upgrade to fix this error. to highlight the fact.

mysql_upgrade output:
Phase 1/3: Fixing table and database names
Phase 2/3: Checking and upgrading tables
Processing databases
information_schema
mydb
mydb.wp_commentmeta Needs upgrade
mydb.wp_comments OK
mydb.wp_links OK
mydb.wp_options OK
mydb.wp_postmeta OK
mydb.wp_posts OK
mydb.wp_term_relationships OK
mydb.wp_term_taxonomy OK
mydb.wp_terms OK
mydb.wp_usermeta OK
mydb.wp_users OK
mysql
mysql.columns_priv OK
mysql.db OK
mysql.func OK
mysql.help_category Needs upgrade
mysql.help_keyword Needs upgrade
mysql.help_relation OK
mysql.help_topic Needs upgrade
mysql.host OK
mysql.proc Needs upgrade
mysql.procs_priv OK
mysql.tables_priv OK
mysql.time_zone OK
mysql.time_zone_leap_second OK
mysql.time_zone_name Needs upgrade
mysql.time_zone_transition OK
mysql.time_zone_transition_type OK
mysql.user OK
mysql.help_category OK
mysql.help_keyword OK
mysql.help_topic OK
mysql.proc OK
mysql.time_zone_name OK
Phase 3/3: Running 'mysql_fix_privilege_tables'...
OK

I decided to recreate my.cnf using the files shipped with MariaDB due to the introduction of new settings and a difference in values for existing settings.