Royal Mail is making changes to the way it delivers mail in parts of Sheffield.
Postmen and women at Halfway Delivery Office who serve the S20 and S21 postcodes are to use new delivery methods and adopt revised delivery routes.
The changes are due to a drop in the number of letters - and a rise in the amount of parcels to deliver.
Deliveries will continue in the mornings and for a longer period during the day.
Many customers will continue to get their mail by lunchtime, but Royal Mail is warning current delivery times will change.
Sector manager Harry Murphy said: “The delivery team and I are fully committed to providing a high quality, reliable and friendly service.”