The "2" toolkit intsaller is for Connexion version 2.
The "3" toolkit intsaller is for Connexion version 3.

There have been severe problems with Connexion version 3 and the "3" version of the authority toolkit, but these may have been resolved with the latest versions.

I have successfully used the current version of the macro with Connexion 3.1 on two different workstations.

If you have problems with the "3" version of the toolkit with Connexion 3.X and if you don't actually need anything that's new in Connexion 3.X, I recommend using Connexion 2.X and the "2" version of the toolkit.