For some time MBServer code has made use of the fact that the search server can return results in json format for rendering search results in the Musicbrainz website. Now that the search server can also return results in a new json format (for use in the public json webservice) mbserver code should use this new format (fmt=jsonnew) rather than the older json format (fmt=json), then we can drop the old format.

Most of the differences between old and new formats are minor so shoudn't be too difficult.