> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/resources/product-resources/end-of-life-product-documentation/os-mastermap-water-network-layer/release-notes/april-2025.md).

# April 2025

This release note provides information about the April 2025 release of OS MasterMap Water Network Layer.

## Feature counts

<table><thead><tr><th width="436">Feature Type</th><th>Count</th></tr></thead><tbody><tr><td>WatercourseLink</td><td>4 733 541</td></tr><tr><td>HydroNode</td><td>4 752 874</td></tr></tbody></table>

## Errors

<table><thead><tr><th width="434">Error Type</th><th>Count</th><th data-hidden></th></tr></thead><tbody><tr><td>Links with spikes</td><td>1</td><td></td></tr><tr><td>Single link loops</td><td>44</td><td></td></tr><tr><td>Multi-link circular flow loops that include River links</td><td>4</td><td></td></tr><tr><td>Multi-link circular flow loops on Drains</td><td>25</td><td></td></tr></tbody></table>

## Product improvements

Details of live and resolved data issues for the OS MasterMap Water Layer product will be communicated on the [OS MasterMap Water Network Layer Known Data Issues page](https://docs.os.uk/os-downloads/networks/os-mastermap-water-network-layer/os-mastermap-water-network-layer-known-data-issues). This page will provide details of their impacts and updates on the expected time frame for their resolution.

## Next release

The next release of OS MasterMap Water Network Layer is scheduled for **July 2025**.


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