I missed the update to 5.11, so I'm going from 5.10 to 5.12.
After the upgrade I get this error page:
Unsupported database type
The database type is unsupported. Please use either mysql for MySQL 3.x & 4.0.x databases, mysqli for MySQL 4.1.x+ databases, or pgsql for PostgreSQL databases. The database information is in your settings.php file.
I'm only having this problem with my local testing machine which is a iMac running MAMP Pro (php4 or php5, MySQL 5.0.41).
The upgrade went fine with the site I'm developing on the production server which is (php4, MySQL 3.23.49 ).
When I develop for this particular site I set MAMP Pro to be php4, but I can't change the MySQL version. I try to keep things as close as possible to the clients hosting server.
Anyways, I didn't and don't have any issue connecting to the database with Drupal 5.10 using php4 and mysql for MySQL 5.
And things work after a clean install with Druapl 5.12 running under php5 and install using mysqli for MySQL 5.
But when I do a clean install of 5.12 using php4 and mysql for MySQL 5, I don't get the option to use mysqli as a database because I'm running php4, if I understand things correctly.
Things break again under php5 and install using mysqli for MySQL 5 as soon as I import the data base tables from 5.10 installation running under php4