STEPS TO REPRODUCE
Preconditions: An older instance of XWiki (e.g. 9.11.8) and an instance of XWiki 10.9 (to which will be migrated) are available. Both instances are configured with Oracle 11.2.
1. Go to the newer instance (10.9) and copy/cut the
folder and replace it (first delete the old one) in the same location on the older version
2. Start the instance and follow the Distribution Wizard through the upgrade process
The upgrade process is completed successfully without errors.
Instead of starting the Distribution Wizard for the upgrade process, the browser gets a 'HTTP Error 500', some huge errors in the console and the upgrade fails. Log attached.
It was used ojdbc8.jar connector.