Epic Games recently revealed Unreal Engine 4.20. It noted new features it brings to developers. Particularly notable are various improvements for mobile and Nintendo Switch development that were originally optimizations made for Fortnite on those systems.
On mobile, Unreal Engine 4.20 makes it easier for developers to optimize gameplay across various devices and specs, and it improves the debugging feature as well. These are among more than 100 optimizations that are part of the new version.
For the Nintendo Switch, tons of memory and performance improvements are part of 4.20, including low latency frame synching for controller input, better texture compression, and support for dynamic resolution and temporary upscaling. There are also significant CPU rendering optimizations.
You can read the full list of added features here.