Kubuntu 12.04b amd64, KDE 4.8.2 packages from Kubuntu PPAs.

In the Server Configuration tab in the Akonadi kcm, there's a dropdown list where you can choose what backend it should use to store its database. In the (K)ubuntu repositories, there are packages for MySQL, PostgreSQL, SQLite and ODBC backends (akonadi-server-{mysql,postgresql,sqlite,odbc}).

The kcm always offers to only pick between mysql and postgresql, regardless of what backends are actually available. This is even if the postgresql backend is not installed at all. Other backends are never listed.

Reproducible: Always

Steps to Reproduce:
1. Install the SQLite backend
2. Remove the PostgreSQL backend
3. kbuildsycoca4
4. kcmshell4 akonadi
5. Open Server Configuration tab and view the Database driver alternatives
Actual Results:  
6. The drop-down menu lists MySQL and PostgreSQL, despite the latter not being installed at all and without mention of SQLite

Expected Results:  
6. The drop-down menu should list the installed MySQL and SQLite backends

I tested this on two different machines and on a new user. Also worthy of mention is that Akonadi is packaged in Kubuntu with the mysql backend as a hard dependency.

I did manage to get it to switch to sqlite by manually modifying the [%General] section of ~/.config/akonadi/akonadiserverrc;

>[%General]
>Driver=QSQLITE3

Opening the kcm now the Database driver menu shows as having an empty selection, and expanding the menu it still lists mysql and postgresql.