Steps in no particular order
From the 1.9 ( I assume still running) download all the users from the admin/user interface as a spread sheet. Using a copy of the file remove collum 1 which should be labelled ID that's the old DB id. Remove the collum password and re instate as a blank collum.
Save the file as a CSV file encoded as UTF8, in the save config make sure the quotes marks are not included.
Next download and save off Moodle all the old 1.9 course backups.
Now Moodle 2.5, create a blank, no users database using the Moodle install new site script, either cli or web, that will create the correct type of DB tables. Make sure you have a new blank moodledata directory before you do the install of Moodle.
Now the hard part reinstall all the old 1.9 backups using the Restore link on the front page or else where.Mind numbing work lots of beverage helps. You will have to ensure that all the course links work as expected, more beverage.
Next from here Page path
- Home
- / ►Site administration
- / ►Users
- / ►Accounts
- / ►Upload user
drop the CSV file in and reload all the users, they will get a email telling them they have new accounts and please change there password. By leaving the password field blank Moodle auto does a random one per user.
Hint you can do most of the reinstall as a Manager, it loads faster than Admin.
This is a very time consuming way of doing it, but, it works.
John