code: public ArrayList<String> hosting_web_serviceName_upgrade_GET(String serviceName, net.minidev.ovh.api.hosting.web.OvhOfferEnum offer, Boolean waiveRetractationPeriod) throws IOException {
  		String qPath = "/order/hosting/web/{serviceName}/upgrade";
  		StringBuilder sb = path(qPath, serviceName);
  		query(sb, "offer", offer);
  		query(sb, "waiveRetractationPeriod", waiveRetractationPeriod);
  		String resp = exec(qPath, "GET", sb.toString(), null);
  		return convertTo(resp, t1);
  	}
docs: Get allowed durations for 'upgrade' option
  
  REST: GET /order/hosting/web/{serviceName}/upgrade
  @param offer [required] New offers for your hosting account
  @param waiveRetractationPeriod [required] Indicates that order will be processed with waiving retractation period
  @param serviceName [required] The internal name of your hosting