We've pretty much tried everything to upgrade our student online courses from Moodle 2.2 to 2.6 without success.

The errors that pretty much consistently come up when the upgrade fails have to with question table/s.

I believe that what makes our Moodle unique is that our course content comes from third-party course content vendors. And some of the courses we've obtained from them not only use various plug-ins but also we have not communicated with them about how they create quiz questions.

So I did some research - looked at question types listed in Moodle 2.2 documentation, a 2.6 site and our student Moodle 2.2 version >Plugins >Question types

Here's what I found -
Student Moodle has these question types that are NOT listed as core question types in Moodle  2.2 documentation or the 2.6 website :

  • Rendered matching (of which there are 7 (+3 hidden) questions in our Student Moodle
  • Missing Type - has 0 questions on the Student Moodle site
  • Random - 30,588 questions !!!
  • Random short-answer matching - has 0 question on student moodle.
What does mean? 
Is the quiz engine helper utility not working to convert the rendered matching question type?
Does "random" refer to how the quiz presents the questions - in a "random" manner so each student gets the same questions but present in random order?

To be continued....