The most significant change was raising the file size limit for custom maps from 8MB to 128MB . This allowed for massive RPGs and high-fidelity custom maps that were previously impossible.
Patch 1.27b (released December 2016) was the final "standalone" patch before Blizzard began transitioning to the modern launcher system. warcraft 3 frozen throne 127b download top
To get 1.27b, you typically need a base installation of the original game (either from old retail CDs or official legacy installers) and then apply the specific update file. The most significant change was raising the file