General questions and discussions.

The old Guild Hall upgrade from Heroes of Might and Magic doesn't work in HotA 1.5.
It would be strange if it did.

So now you need to choose which level 5 spell you want, because it can only be researched once.
Question about the library in the Tower - can you research in the additional library slots there?

It seems that now it's desirable to build Guild Halls in different castles if you want to get Fly, Damage, and Implosion spells, since it's not possible to do it in one.

Sorry for the noob questions.