GZDoom 2.4.0

New render features

• Doom64-style color properties for sectors (i.e. different color settings for floor, ceiling, walls and sprites)

New scripting features

• Script versioning to account for syntax differences between versions
• Fully scripted inventory system
• Fully scripted menu system
• Scripted event system
• Printf-style string formatting function for ZScript
• Dynamic arrays for ZScript
• More access to map data from ZScript
• User definable actor properties
• Separation of scripts into UI and Play parts to have better access control
• Exported obituary code to ZScript to allow more flexibility when handling special cases
• SectorTagIterator and LineIDIterator classes to search for tags

Other

• Added GetActorFloorTexture and GetActorFloorTerrain ACS functions
• Added new PRINTNAME_ constants for retrieving next and secret next level in ACS
• Added per-sector settable fog density
• Fixed handling of sector action things with special trigger semantics
• True color fonts can be defined in FONTDEFS
• added a BOUNCE_NotOnShootables flag to address an old design bug in the bouncing system
• added StealthAlpha actor property for defining a minimum visibility value of a stealth monster

... and many more smaller additions and fixes.