finally everything seems to work out fine and the upgrade from 1.9.xx to 2.03 is completed .
After the correction of all database commands, install.xml and upgrading version.php, I had to do some last database command corrections, which were easily done with moodle in "debugging-mode".
Also the directory (structure) of the logo and the language files changed (I also completed the english language files of the question type).
In the next step I created the new backup and restore files. I read the backup 2.0 and restore 2.0 developer docs, but finally it was easier for me to use question type truefalse and numerical as a model. After some tests with different moodle 2.03 instances failures were corrected very fast.
After this I implemeted the db upgrade file to drop the enum fields (, but I think the question type doesn't really need that).
Finally I created the new db install file to fill the db table during installation. This is a really great upgrade in moodle 2.0, because in 1.9.xx I checked the db tables every time an instance of the question type was created (, or a restore procedure was started), which was very bad for the performance.
I spent some time on testing the actual code and the only failure I found is that in the review correct answers are indicated red sometimes (, instead of green or no indication). Do you have any clue how to correct this bug?
This week I will start with the upgrade from 2.0 to 2.1. Can you give me any further advises? How is your upgrade doing?
Actually I didn't have a lot communication with my university so I don't know yet if I can publish the accounting question type.