Hello everyone!

I honestly never thought I'd be making a topic like this in 2026, but here we are.

For the past month I've been working on something that I know many old LCPDFR players have wanted for years:

A fully functional version of LCPDFR for GTA IV: Complete Edition.

Like many of you, I grew up playing GTA IV and LCPDFR. I started modding GTA when I was around 10 years old and over the years I've learned 3D modelling, vehicle creation, map modelling and C++ programming. I'm far from calling myself a professional developer, but I've always enjoyed reverse engineering and recreating systems while keeping them as close to the original experience as possible.

One thing that always frustrated me was how unstable LCPDFR became over the years. Back on version 1.0.7.0, random crashes were simply accepted as "part of the experience." When Rockstar replaced the legacy version with GTA IV: Complete Edition, things became even worse because the original platform LCPDFR was built for essentially disappeared.

Instead of giving up, I decided to see whether it would be possible to make LCPDFR work on Complete Edition.

Over the last month I've been reverse engineering the ScriptHook and AdvancedHook loaders together with the LCPDFR DLLs, analysing how the event managers, handlers and internal systems communicate. Using AI as an assistant for repetitive analysis and my own C++ modifications, I've started rebuilding compatibility layer by layer.

Current Progress

• ✅ LCPDFR loads on GTA IV Complete Edition (1.2.0.59)

• ✅ Modified DLL loaders adapted for Complete Edition

• ✅ Major internal systems reconstructed

• ✅ Roughly 50–60% of the project completed

• ✅ Significantly improved stability compared to the original setup

The goal isn't simply to "make it launch."

My goal is to create a version that feels like the original LCPDFR while running reliably on modern systems, including Windows 11, modern ScriptHook environments and DXVK. If everything goes according to plan, I'd like to achieve stability close to 99% uptime with little to no random crashes.

This isn't intended to replace the original developers' incredible work. Quite the opposite—this project exists because I want to preserve it and make it playable again for today's community.

If there's enough interest, I'll continue posting development updates, screenshots, videos and technical breakdowns of what has already been achieved.

I'd also love to hear what features or systems people would most like to see working again.

Maybe it's finally time to bring LCPDFR back to life.

Thanks for reading, and I look forward to hearing your thoughts!

Hi Max911,

LCPDFR crashes certainly became all too familiar. People have it easy now with LSPDFR handling things that LCPDFR would have folded on. This project sounds great! It would be nice to be able to jump back into some LCPDFR.

I'm not sure if I am reading about your methods wrong, but are you aware that LCPDFR is open source? https://github.com/LMSDev/lcpdfr_public

Hey! Fantastic to hear about your project.

LCPDFR as mentioned by Gan Ceann, is already open source, and a great deal of engineering effort to make it run on Complete Edition has been made by us; https://www.lcpdfr.com/downloads/gta4mods/g17media/26726-compatibility-patch-for-gta-iv-complete-edition/

Our compatibility patch suite already fixes Scripthook .NET, patches aru's C++ scripthook and fixed AdvancedHook. The legacy edition that ships with LCPDFR to this day, supports Complete Edition.

Any further work is always appreciated, and we look forward to reviewing any pull requests or patches you make against LCPDFR.

Hey guys, thanks for showing your interest and efforts to reply!

Also a big thank you for providing me the knowledge that it became open source... I always remembered it wasnt open source but it made sense when i saw the 2022 release date during the pandemic. I was in the middle of the pandemic busy with ELS emissive mods for IV so i probably never noticed. Hence this is the reason i thought now it would be a great oppertunity to pitch the above idea for a own made version. Nonetheless the information you guys provided me was exactly what i wouldve needed at one point as the tools for reverse engineering the loaders was too small and it missed alot of natives, handles and stuff which caused strange behaviour of LCPDFR ingame.

As of now i downloaded the open source git and restarted with a clean loader while letting the AI tool know to always use my lcpdfr_public folder (git source on my pc) as reference points for structure flow. Already alot of improvements have been made, in the coming weeks i will post more updates, screenshots and future ideas that i have to add.

For now i can share with you guys that my first plan after making the loader fully functional is to enchance the LCPDFR dynamic, re-designing callout events, together with a improved pull over system including a new way of calling traffic stop backups as where the units will either park behind you in yet a calm scenario and will immediately pull up into a tactial position when a vehicle or driver is either wanted to approach for a professional arrest. This can be requested by the player by a hotkey after the vehicle has been pulled over. Like "F1 = No Backup "F2 = Code 2 Backup" "F3 = Code 3 Backup" and then proceed with the traffic stop events.

The things so far what i have implemented for ELS is to reduce the siren chaos ingame from all the units who are chasing.
The system i created so far is capable of when units pull up to a scene to determine how many sirens in a radius are still active and decide whether its too many.
Kinda like in real life where some officers quickly hit the siren button to turn it off and as where some officers jump out and start to run making the wail sound in the distance. This effect is now also included in my LCPDFR version, during chases the cop cars will also use the same way of using sirens where i also added if they are turned off they will shortly use the wail or yelp/horn on intersections and after it will drive along with just the lights.

One of the last thing that i will do once my version has been made is to implement it also with RTX Remix, specifically finding a solution to the police lightbar lighting issues that it has right now, if you dont know RTX Remix cant render proper scene lightning from the lightbar as the script/textures are setup differently than how RTX projects it (As to my simple understanding and ability to explain).

More ideas are also really appreciated so if youve had a wish or dream function to see being implemented in LCPDFR please reply underneath as i would love to hear from you and add it into the game to do something back for the community.

Edited 18 hours ago18 hr by Max911