AddressBase Core Data Issues, Service Disruptions and Planned Maintenance

This page provides the details of known data issues and service disruptions impacting the AddressBase Core product. It also provides information on any planned maintenance periods.

Live known data issues

There are no live known data issues for AddressBase Core at this time.

To report an issue not currently listed here, please visit the 'Contact us' page on the OS website.

Resolved data issues

Incorrect GSS code values for address records in Sheffield and Barnsley

The AddressBase Core product refresh scheduled for the week commencing 11 August 2025 only contained changes to correct the GSS (Government Statistical Service) codes for Sheffield and Barnsley. Changes from Local Authorities, Royal Mail or Ordnance Survey were not available in that week's product refresh.

The AddressBase Core product refresh scheduled for the week commencing 19 August 2025 successfully included two weeks’ worth of change from Local Authorities, Royal Mail and Ordnance Survey.

Data Issue Description	Last Update
An issue was encountered following the change in GSS codes for Sheffield and Barnsley that took effect on 01 April 2025. This has resulted in AddressBase Core currently displaying the historic GSS code. The previous and current GSS code changes as of 01 April 2025 are detailed in the table below:	GSS code fix planned for the week commencing 11 August 2025, with full implementation during the week commencing 19 August 2025. 10/06/2025 – Under investigation 12/08/2025 – Fix successfully implemented and released week commencing 11/08/2025. 19/08/2025 – This week's release contained all previously suspended updates.

Service disruption

There are no live service disruptions affecting AddressBase Core at this time.

Planned maintenance

No maintenance events are currently scheduled that will impact the availability of AddressBase Core.