ZTE promised that Axon 7 will be updated to Android 8.0 Oreo in 2018, but no timeline has been provided. Now ZTE has started to rollout Android Oreo 8.0 beta version in US who are in the part of beta program. ZTE is on its track to release the update. Previous reports shows that the update will be available around April.
Beta update does not provide the full changelog, however the update brings the latest January Security patch. Hope soon the final update will be rolled out to the users soon with the latest security patch.