What was just improved (from Revision version 1.3 to 1.4, July 2018)?

Very late reply but the latest revision 1.4 just changes GOG installer data.

Changed files:
goggame-1207658995.hashdb
goggame-1207658995.info
goggame-1207658995.script
goggame-galaxyFileList.ini
goglog.ini
Launch Deus Ex GOTY.lnk
unins000.dat
unins000.exe

Removed files:
webcache.zip

Thank you for the reply. :)
It's not clear what these updates have done, though, so I won't bother re-installing the game just to check. (I don't use Galaxy and cloud saves, which is mostly what recent updates accomplish.)

From the Mod DB page:

UNATCO HQ (First Visit):
The items taken from the bodies of the terrorists killed during the mission end are now visible inside the armoury like the UNATCO troopers say.

Chapter 3:
Fixed level transitions between Airfield and Hangar so you don't accidentally go to the wrong teleporter in Hangar.
Made all the terrorists in chapter 3 friendly after Paul tells them to stand down.

Brooklyn Bridge Station:
Added more detail to the upper level.

Ton Hotel (Second Visit):
AI is smart enough to disable the grenades outside Paul's room on realistic difficulty.

New York Majestic 12 Facility:
Added a pistol at the start to make it a bit easier.
Expanded armoury and placed the player's ammo inside.

Canals near Wan Chai Market:
Fixed John Smith not having a prototype nanosword on him on Biomod.

Tunnel near Wan Chai Market:
Can no longer open the 55655 door just by right clicking it. (Still breakable though)

Wan Chai Underground Mall & Lucky Money:
Added new music for inside the club.

Versalife Advanced R&D (Level 1):
Increased the volume of the WiB convos.
Made Maggie and Page not look at the player.

Chapter 9:
Friendly guards have new boot textures.

Dockyard:
Added key for the valve door that was missing.
Gate guards don't mind lockpicking if they know who you are.

Area 51 (Sector 3):
Added Helios' unused final infolink.

Area 51 (Sector 4):
Changed Page to stop mocking you if you complete the Tong or Helios missions, just like the Everett one.

Modifiers:
Can no longer gain infinite ammo from grenades on some modifiers.
Fixed a crash during Real Time UI if having the UI open when touching a teleporter.
Manhunt:
NPCs before chapter 5 will not mind you killing the Secret Service and will help you kill them at Liberty Island or at the Hangar.
Secret Service won't spawn within 16ft of the player.
Secret Service will attack the NSF.
Fixed Secret Service not respawning correctly on difficulties past easy.

Gameplay:
Added challenge system.
Added custom difficulty option.
Allowed NPCs break objects that the player is hiding behind in very rare cases.
Autosave now checks every second for a chance to save at the start of a level (for areas that immediately have an infolink).
Fixed Biomod's challenge system not working.
Fixed losing ammo when throwing a grenade or throwing knife when none spawns.
Fixed the AI not reacting to the light aug.
Looking at something with the binoculars displays the name of what you're looking at and its distance.
NPCs rubbing their eyes won't stop rubbing their eyes after a door opens.
Quickloading while dead or at the main menu no longer asks you to confirm.
Stunning an enemy who's rubbing their eyes now goes to the stunned state.
Normal only changes:
Augmentations now display their true level in the menu when synthetic heart augmentation boosts them (pre-boost level).
Augmentations can no longer be upgraded past level 3 if the player has synthetic heart augmentation.
Augmentations don't play the augmentation loop sound if they're a passive augmentation.
Augmentations that are upgraded now turn back on if they were on before the upgrade.
Fixed being unable to upgrade augmentations to their max level if they were on and being boosted by the synthetic heart augmentation.

Misc:
Added HDTP infolink icons.
Added an option to disable the hum of augmentations.
Added an option to disable the idle beeps from turrets.
Added an option to display the player's speed on screen.
Added grenade launcher to AllWeapons cheat.
Added new readme to the Help folder.
Added unique skinned weapons around the game.
Burp sound from soda now comes from JC instead of the soda.
Changed flamethrower fireball to unused texture.
Disabled NPCs looking at you if they are on fire, rubbing their eyes, or stunned.
Enabled lip syncing and blinking for NPCs who are either: dancing, sitting, waiting for someone, going to someone, running to someone, burning, avoiding a projectile, avoiding a character, backing off from a door to open it, opening a door, taking a hit, rubbing their eyes, dying, or falling.
Enemies no longer play their critical damage sound when stunned.
Fixed "Off to a Great Start" achievement being awarded just from picking Winslow up.
Fixed attacking friendly NPCs who had their heads turned to look at you keeping their heads turned after they turned hostile and attacked you.
Fixed being able to pickup used flares.
Fixed crashes when the game tries to play Revision music that is open in a media player.
Fixed crouch walk animation not working for HDTP JC in Biomod/Shifter.
Fixed item refusal for flares on carcasses.
Fixed sabot being referred to as 'mags'.
Fixed survival levels always saying they're in Paris.
Loading the main menu resets the game speed to normal.
Made cigarettes breakable.
NPCs who are rubbing their eyes continuously blink.
Randomized MJ12 troop faces.
Stepping on a fire hydrant now makes a metal sound rather than grass.
Upgraded flamethrower fire on walls from 32x32 texture to 128x128.

Thank you for the compendious response.

After installing GMDX (so that I now have three installations of Deus Ex :/) my 32-bit system has random crashes to the desktop, so I'll probably re-install the vanilla and play through Revision, before uninstalling it and playing through the GMDX version.

Also, well done keeping on improving the game! That's quite a task list — kudos. :)