We're going to try and do two things going into Season 5.
1) Season 5 Characters
New city. New game edition. New characters. We're still debating on the specifics, but I think we're going to largely start everyone on a level playing field. So no straight conversions of characters to SR5.
There are a LOT of reasons for doing this, but one of the biggest is that even if we did allow players to port characters over, a lot of gear, rules, and even PC races that are being played won't be available for quite some time. Even with the most aggressive schedule possible, it would likely be at least a year, probably 2 or even longer before all of the various gear and stuff from SR4 saw publication in an SR5 book, meaning that they wouldn't be legal to use in Missions until then.
Plus even with the karma cap that we went with going into Season 4, we still had a lot of players who kinda cheesed the cap, starting Season 4 with 100+ karma, putting some characters that play the convention games regularly well over 300.
2) Prime Missions.
Long Talked about, but various delays prevents them from coming to fruition (writers dropping out of projects, mostly. I've been cursed with these). These Missions won;t be published as often as Season 5 ones, but will hopefully we'll be able to do 4 or so a year. Season 4 characters will be able to transfer to Prime Runner games (Though you'll have to rebuild the character from scratch, and deal with the limitations of only a core book to start with). So your Season 4 characters won't be lost, they just move into a new tax bracket.
It's not ideal, but dealing with Seasonal transitions and a new game Edition is never ideal. There are always problems, and hopefully these will allow for the smoothest transition and will help make certain that everyone is starting at the same general play level.
Bull