Where to find it (archive): Look for WaterSystemQuickStart and WaterVisuals in the 4.26 docset.

The documentation details an overhauled nDisplay configuration system. It allows developers to map a single Unreal Engine project across multiple synchronized LED screens and computers using a new, visual 3D config editor.

The Mobile Previewer was upgraded to match Metal and Vulkan desktop specifications precisely. This reduced the performance delta between editor viewports and actual device deployments. Cascaded Shadow Maps (CSM) vs. Distance Field Shadows Use CSM for dynamic close-up character shadows.

When Epic released 4.26 in late 2020, the documentation received a massive overhaul to cover four major pillars that were either new or substantially rewritten :

Reviewing the .udn (Unreal Documentation Network) files inside this directory provides offline text documentation, unedited code snippets, and structural blueprints that are no longer hosted on the public internet. 26 Movie Render Queue framework?

The Vault Unlocked: Navigating the Unreal Engine 4.26 Documentation

The cloud system uses a ray-marching material format. The engine steps through a 3D texture volume, accumulating density and calculating light transmittance.

UE 4.26’s Chaos docs focused on:

For mobile developers targeting iOS and Android, 4.26 brought essential updates to the Mobile Forward Renderer. Mobile Desktop Previewer

The 4.26 docs exclusively warn that the PhysicalMaterialMask is stored in TMap differently than in UE5. If you follow the UE5 guide for importing masks, your 4.26 project will crash. You must use the legacy LayeredTexture approach outlined only in the 4.26 PDF archives.

Version 4.26 elevated digital human rendering by moving the strand-based hair system out of experimental status. This framework allows direct import of .abc (Alembic) files from DCC tools like Maya or Houdini.