Hello Ludek!
Thank you for moving my answer into the correct form and the linked articles. I will work through them in the evening.
I do not know if 11.0 or 11.5 is used. I will have to check this with the customer.
The customer told me that the migration of the reporting feature is not a "must have" on the requirements list, as the system is already "deprecated" and keept alive to check up old data.
Alex