From version 18.104.22.168 forward, it is now possible for you to customize your own dignities table. This feature come from the fact that some astrologers use modern dignities principles, namely regarding the outer planets (not know by Ptolemy or Dorotheus).
You can do this, in the general settings menu of Tetrabyblos, by clicking in the “Dignities” tab. Here’s a screenshot:
The image is self explanatory. After defining your own criteria, save them. Now, in the admin settings menu, you can choose as the essential dignities table, your Custom Table, which will be use in the calculations.