Gemini Api Ephemeral token not working

Good catch! I tried this:

const token = await client.authTokens.create({
    config: {
      expireTime, // Default 1 minute in the future
      newSessionExpireTime: new Date(Date.now() + (1 * 60 * 1000)),
      httpOptions: {apiVersion: 'v1beta'},
    },
  });

It threw this error: “Error getting ephemeral token: ApiError: {"error":{"message":"","code":404,"status":"Not Found"}}

Is ephemeral tokens only supported in v1alpha?