The only person who can definitively answer that would be the lead dev Peter. And he rarely ever answers posts of this nature. I there will be at least another RC release before there is a ST.
Two days ago Peter added a "New stuff in 1.7-rc6" to the WHATSNEW.md at github.
source: https://github.com/protich/osTicket-1.7/commit/81d180a40acff3814d180afa82371f8a52d3e24a(https://github.com/protich/osTicket-1.7/commit/81d180a40acff3814d180afa82371f8a52d3e24a)