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 R4305
01 Mar 2026
Fixed an issue where DeHackEd things with DoomEdNum -1 were shown in the placeable list of things. Fixes #1304
Ultimate Doom Builder R4304
01 Mar 2026
Fixed an issue where the line activation was not saved correctly in Hexen format. Fixes #1306
Ultimate Doom Builder R4303
28 Feb 2026
Blockmap Explorer Mode: drawing is now handled correctly when resizing the window. Fixes #1313
Ultimate Doom Builder R4301
26 Feb 2026
Fixed installer to include the Blockmap Explorer Mode DLL
Ultimate Doom Builder R4300
26 Feb 2026
Some fixes for building Blockmap Explorer Mode on Linux