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 R4292
07 Feb 2026
ZScript: added support for norollback keyword (#1302)
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