Note: Unless you are using a severely outdated operating system or CPU, you most likely want to always download the x64 (64-bit) version of Ultimate Doom Builder.
The 64-bit version has less limitations on the total size of the project that you can load and edit, while the x86 (32-bit) version of Ultimate Doom Builder only exists for compatibility with older PCs.
If not sure, follow these instructions to find out whether your system is 64-bit: Which version of Windows operating system am I running?
The 64-bit version has less limitations on the total size of the project that you can load and edit, while the x86 (32-bit) version of Ultimate Doom Builder only exists for compatibility with older PCs.
If not sure, follow these instructions to find out whether your system is 64-bit: Which version of Windows operating system am I running?
All recent versions
Ultimate Doom Builder R4291
01 Feb 2026
UDBScript: directories starting with a dot are not shown in the script browser anymore
Ultimate Doom Builder R4289
31 Jan 2026
Move ZDoom stealth monsters to own folder (#1298)
Ultimate Doom Builder R4288
31 Jan 2026
Fixed getting revision count in GitHub Action to build flatpak
Ultimate Doom Builder R4287
31 Jan 2026
More fixes for flatpak build
Ultimate Doom Builder R4286
31 Jan 2026
Fixes to GitHub Actions for building the latest flatpak