Redux is a large-scale modification that attempts to modernize Doom 3 with a massive overhaul of the graphical, sound and UI aspects of the game along with bug fixes, restored content and new features.
The display font used for armor, health and ammo count has been changed to get rid of the kerning issues that were only worsened by the widescreen stretching. It is now similar to the one that is being used in the BFG Edition.
The stamina and weapons bar have been moved upwards and various elements have been realigned to improve spacing. The redrawn stamina bar texture has also been updated to remove overlaping with its border.
Here's the original 2016 release's HUD for comparison: Moddb.com