Posting b/c you shouldn't need to dig through 4 pages of thread to figure out what's going on with this thing...
v3 (front page download) works up to 1.27a
v4 (
link) works for 1.27b
No current multiplayer emulators work for 1.28. The author seems to be taking a break from working on this. The only current, pre-baked option to really test multiplayer functionality locally is to switch versions to 1.27b or earlier -- good luck!
As a last resort, to stay on 1.28, you can also probably run another instance of Warcraft from a sandboxed or otherwise virtual environment on your machine. Look up Sandboxie if you're that desperate to test on 1.28