When printing a Royal Mail label there is no longer a Saturday Guarantee logo present on the label.
When accessing Shipping > Integrations > Services > Edit > Saturday Guarantee option is no longer visible as well.
Royal Mail has extended their offer of Special Delivery services by 9am and 1 pm from Monday to Friday to include Saturdays automatically. If the parcel is shipped on a Friday using one of the above services, it will be delivered throughout the day on Saturday and there will no longer be a need to enable Saturday Guarantee in the settings.
This applies to all Special Delivery services with 'Special Delivery Guaranteed 1PM' and 'Special Delivery Guaranteed 9AM' in the name.
In addition to this, Royal Mail have also introduced 9 new Special Delivery Services which will be delivering by 'end of next day' including Saturday and Sunday. These services will have 'Special Delivery GTD NextDay' in their name.