Zwift and iPhone 66s - No Longer Works

Hi all, since the latest Zwift update when using Zwift on my iphone 6s there are never any other riders in any of the worlds. If I log in with a friends iphone 7 or my ipad it works fine every time. I have done all the usual checks, router reboot, network checks etc etc but the above proves something has changed in Zwift. I know there has been work to limit other riders in the worlds when connecting via older devices but I wasn’t expecting to be Billy no mates.
Anyone else having this issue?
Thanks, Paul