Weak BI tools like Qlik doesn't properly support JSON as an input format. Given flat json format introduced in story #31087, the list fields are exposed as JSON array {"list_field": ["a", "b"]} but it's not possible for Qlik to natively understand this format and requires either complex QlikSense script or external scripts that, for some reasons, cannot be used. List values are easier to deal with in Qlik when they are strings with separators.

As we already have an output_format=[nested|flat] parameter, we introduce a new format flat_with_semicolon_string_array that will produce {"list_field": "a;b"} for list fields (other fields are not affected). The reason behind this choice are:

• Add an output_format instead of having a new parameter avoid to have a validation logic like output_format=nested & separator=comma that would produce garbage
• Usage of semicolon as separator because it's less likely to be a value in list fields.

Note: if a tracker have semicolon as part of field values, using flat_with_semicolon_string_array will produce an invalid result.