What is an errata list?
An errata list is a list of specific corrections of formal errors (layout, correcting printing errors, language errors, etc.) that you wish to make to the submitted thesis before the disputas. Correction of formal errors in practice means the text is made coherent or linguistically correct, not to clarify or change the meaning of the text.
The provision that you cannot make substantive changes also applies if before the disputas you learn that a submitted article is approved or published by a publishing house but in a revised form. It is the submitted article manuscripts that will form the basis for the disputas. But you can in the preface to the printed thesis refer to the final journal article - if you have time to do so.
To whom and when should the errata be delivered?
As soon as you discover errors in your thesis you should write an errata list. You must apply to the department for permission to correct errors in the thesis before it is sent for printing. Remember that the department must have time to assess your application, so you need to allow plenty of time. If you have made changes which the department or the evaluation committee deems to be substantial, these changes will not be approved.