STEPS TO REPRODUCE
- Unzip a fresh instance of XWiki (e.g. 11.10.10)
- Login as Admin
- Create, update and comment a page
- Create an user (e.g. U1)
- Login with U1
- Go to Notifications Preferences and set Pages toggles to ON (which also sets ON all watch toggles)
- Close the instance
- Go to the newer instance (e.g. 12.6.2) and copy/cut the
folder and replace it (first delete the old one) in the same location on the older version
- Start XWiki and follow DW
- On 'Step 5 - Events migration' migrate events from 'All time'
- Login with the user U1
- Observe the notifications list
There are no events in user's notifications list, as the Pages toggles were set to ON after the page was created, updated and commented by Admin on the old instance.
The events are displayed nevertheless in user's notifications list although before the upgrade they were not present there (there's even the U1's profile creation event included).
This may lead to user's notification list being cluttered if there are many events on the wiki.