Hi Pete, been awhile since we talked! Hope all is well with you. Anyway, I thought I might share some insights that may shed some light on this. I get the impression that converters have fallen out of favor over the past several years possibly due to concerns over intellectual property rights or maybe sensitivity for proprietary file formats (leading to purposely avoiding conversion between different vendor's file formats for rule files). Just my personal opinion. Another interesting aspect is that Calibre capability has grown very much over the past several years and with no factory support for those converters they would be missing many modern capabilities anyway.