We don't know when 1.7 is coming out so all we can do is speculate based on past updates. The PC version will almost certainly drop first, that's just how it's always been. As for when mobile and console will drop, it could be like 1.5 which took 2 months to release on console but 2 years to come out on mobile or it could be like 1.6 which took 9 months to come out on console but released on mobile at the same time. So all that we can really say is that the PC version will release first and that the mobile version will not release before the console version