Recently Essential phone was updated directly to Android Oreo 8.1 by skipping Oreo 8.0. It seems Razer phone also following the same path. Razer has released a Developer preview and the update is already available for download. Razer has announced that the finalized version of Oreo will make it to its smartphones in mid or late April.
If you are interested in downloading the update make sure that the Razer smartphone is not the primary smartphone. As the update is the developer preview and it might have bugs or issues. During the installation it will erase all data from the device.