Filter suggestions by label

I’m trying to filter suggestions by label but I can’t get it to work.
I’m trying with this url /suggest?query=fre&num=5&fields.label=personal

I read a comment on this page how suggest filter by label · Issue #1167 · codelibs/fess · GitHub from 19 Jul 2017 that this feature should be supported in next release.

How is the url supposed to be in order to filter suggestions by label?

Best regards

Try /suggest?query=fre&num=5&tags=personal.