There is literally no point in creating brand new characters and converting them from one edition to the other, rather than simply making brand new characters for the new edition.
The trouble with any conversion is that SR4 characters are weaker in absolute terms than their SR5 counterparts, but relatively stronger. In other words, they might only have one 6, but that 6 is better than most NPCs they will meet, rather than being a respectable but middling ability. The other problem is that augmentations and gear have changed so much - dice pool boosters and initiative improvements are much more expensive, deckers and riggers require expensive decks, and so on. It is better to rebuild them with SR5 rules, then add Karma equal to what they had earned.