The macOS binary was recompiled with an older Xcode version and re-posted. Nothing else was changed, but we discovered that building with the latest Xcode tools causes some issues with the program, such as the inability to iconify with F4 on macOS 10.13 High Sierra.
If you are not running macOS High Sierra then you do not need to re-download the game, but if you are then you may want to do so to avoid running into that problem.
I also noticed I had messed up the source archives slightly, so I have re-posted those. The only difference was that the originals had outdated title.png/title.psd and BZFlag.nsi (the Windows NSIS installer script) files showing version 2.4.13.
"In addition to knowing the secrets of the Universe, I can assure you that I am also quite potty trained." -Koenma (Yu Yu Hakusho)