27 January 2025

This release note provides information about the release of the AddressBase Core product on 28 January 2025.

Update to the location of AddressBase Core technical documentation and release notes

AddressBase Core technical documentation (including technical specifications, release notes, getting started guides, etc.) is now available on the new OS Download Products’ Documentation Platform (https://docs.os.uk/os-downloads). This platform is the new central location for all technical documentation for OS Premium and OpenData Download products (such as AddressBase, OS MasterMap Topography Layer, OS Open UPRN, etc.).

Over the next few months, the old PDFs containing product technical documentation will be removed from the product pages of the OS website and replaced by links to the refreshed documentation on the new platform.

Release notes for AddressBase Core are available on the new platform (https://docs.os.uk/os-downloads/addressing-and-location/addressbase-core/release-notes); simply navigate to the new platform and click Addressing and location portfolio > AddressBase Core > Release Notes. Static PDF release notes for the AddressBase products will be replaced by digital release notes on the new platform over the next few months.

Known issues will now be displayed on the AddressBase Core Known Issues | OS Download Products' Documentation page, rather than detailed in the release note.

Record counts

Product	Full Supply record count	Change-Only Update record count
AddressBase Core	34 578 163	23 201

These counts are based on a Managed Great Britain Set (MGBS). If you ordered your national coverage via the online ordering system using a polygon outline, your counts may differ.

Product supply comparison

There is a difference in record counts between taking a national Managed Great Britain Set (MGBS) and the national 5km-tile supply. This is because the two supplies use different selection criteria. The difference in record counts is shown in the following table, allowing you to validate your data holdings once you have loaded the latest release of AddressBase Core.

Product	MGBS Full Count	National 5km tiled supply	Difference
AddressBase Core	34 578 163	34 578 155	8

A small difference in record counts is expected due to there being several features supplied in the MGBS which fall outside of the tiled area.

Changed records

If you receive a Change-Only Update (COU) supply for your AddressBase Core product, you will receive Insert, Update and Delete records within the supplied file. The following table details the numbers of these records which can be expected in the COU supply of the product:

Change type	Count
Inserts	7 561
Updates	23 201
Deletes	2 489
COU populated 5km tile count	3 014

Source data currency

The following information relates to the currency of the source data used in the creation of this release of AddressBase Core:

Data source	Date
Royal Mail Postcode Address File (PAF)	24 January 2025
National Land and Property Gazetteer	24 January 2025
One Scotland Gazetteer	06 January 2025
OS MasterMap Topography Layer	28 November 2024