The Creators Update is now hitting Release Preview Insider phones - or at least some of them. This comes a few days before the likely rollout to 'production' devices. The full official availability list is covered in my recent table, though there are some question marks over Insider provisioning for older devices, as evidenced by today's availability missing out (at the time of writing) the likes of the Lumia 930 and 1520. Does this mean that provisioning for these of Redstone 2 has already been pulled on the Microsoft servers?
Not necessarily, this might simply be a staged process. We shall see. It would be a shame to leave such device owners on either the slower Anniversary Update or an 'unfinished' previous Creators Update build. Microsoft has referred to such 'unsupported' devices continuing to get cumulative updates, but I'm still researching what exactly this means in the real world.
We're seeing 15063.251 now available for several editorial 950/XL smartphones running the RP rings, and you can download/check for this in the usual way in 'Settings/Update & security/Phone update'. It's a whole new branch of the OS, but it's not a big download, thanks to recent moves by Microsoft to implement an incremental update regime.