How to safely change the delimiter in $by_category projection?

I’d like to change the delimiter of the $by_category system projection from - to .``.Can you give me some advice how to do it safely?

I was able to change the definition using PUT /projection/$by_category/query?&emit=1 but event store still creates streams according to the original definition. Even doing something like disable, updateQuery```, enable` didn’t help.