It looks like #6 will be the last. Writers have moved onto other things, and publisher isn't responding to questions. AFAIK the license period is also ending later this year (*), and given their pace, there's zero chance of a new 'episode' in that time.
I've heard the relationship was tumultuous at best, and now we'll end up have a single (and pretty crappy) 'episode' of 'Return to Destiny' after all the hype. Sales have also been pretty terrible, when looking at the charts. (E-copies on Amazon seem to have done alright though)
Geez...there's so much potential here -- how hard is it to get it right?
(*) Just count the months back to the original kickstarter (late 2015), and it's pretty standard that license contracts are 2-3 years. In this case, if it's 3, that'll bring us to late 2018.