Justin Sun just announced no immediate coin exchange/swap for current steem. Steem will run on it's own for foreseeable future with Tron resources helping make it and Steemit.com thrive.
Of course, since the AMA (this morning) he is saying on Twitter that the migration to the Tron network is now beginning.
Looks like that has since been deleted...
https://steemit.com/steem/@jrcornel/steem-the-confusion-continues-justin-sun-deletes-latest-tweet