Technically it would be possible, but could be quite a bit of work, depending on what you want to convert.
Most 3.5 hacks are ports of 3.0 hacks anyway, so wouldn't need converting backwards.
Thank you Paul, it's good to know that it's at least possible. The hack that I'm trying to convert is https://vborg.vbsupport.ru/showthrea...ght=sparklines . The only thing that I can't figure out is where I should put the code of the plugin, but I'm still testing. :rambo: