> ## Documentation Index
> Fetch the complete documentation index at: https://docs.speckle.systems/llms.txt
> Use this file to discover all available pages before exploring further.

# Viewer developer notes in 2026.9

> 2026.9 notes for Viewer packages are not on this preview yet. Use the current Viewer developer docs.

<Note>
  This is 2026.9 preview documentation. Coverage here is incremental: a page exists only where
  2026.9 differs or is newly documented.
</Note>

2026.9 developer notes for Speckle Viewer packages are not on this preview yet. Use the
[current Viewer developer documentation](/developers/viewer/introduction) until those notes land.

<Note>
  Package-level Viewer documentation is planned for when compatibility mode turns off on **1
  November 2026**. For the web 3D viewer in the product UI, see [3D viewer in
  2026.9](/next/3d-viewer/introduction).
</Note>