Alphabetical is the default sort order for text and category fields in Omniscope. If a new value is added it will go to the bottom of the list, and you will have to reinforce the rule by clicking on the 'Sort alphabetically' button.
If this happens on a regular basis, you could use the Field organiser option and pick a sort list to ensure the new values fall into place - see the second image.

Hi Paola, I understand the two options you describe.
As the datasource is from a client, we cannot predict the new data values, therefore the second option is not going to work. We would like to be able to select in the dashboard in the filter panel that category fields are ordered alphabetically. Alex thinks that the best option now is that, before we send the data into the dashboard file, to work with sorting blocks to have the data ordered the right way.

Do you agree that this could solve our problem? Thanks for helping us out.

Yes - add an .iok file that will take over the new data, add an Aggregate block to create a unique list of values (keep just that one field), run through the Sort block, then publish the csv that will always be up-to-date.
Use the Server to automate the task.

Hi Paola,

This solution works until there any new values are added. Whenever a new value is added, this value appears at the bottom of the array.

Is it maybe possible for you to share screens for this issue and walk us through?

Thanks in advance