If you have installed the Drag[en]gine and/or IGDE using repositories or market place updates arrive automatically.
Otherwise get the 1.4 release files from the Download Section. You can install it over the 1.3 release but it is recommended to uninstalling 1.3 first to keep the game engine directory clean.
To develop games you do not need the game engine source code. Just install the IGDE, create a project, run and distribute to *.delga file and you are done.
Some of the new Features besides others
Added IES Image Module able to load *.ies files (IESNA LM-63 Photometric Data File).
Added support to preview light materials in skin editor. Engine includes now an always present pack of common IES profiles.
Replaced old tone mapping operator to improve image quality due to better shaped curve.
Added support for emissivity.camera.adapted to allow emissivities to be relative to camera adapted intensity (aka maximum intensity).
You can find the full Changelog of the latest release on this Perma-Link:
Changelog Latest Release
If you have questions, suggestions or other inquiries you can PM me here or stop by the Discord Channel.