The weakest castle in Heroes of Might and Magic IV!

But the portal couldn't be used during battle... Maybe you're confusing it with teleport?

Why can't it be used? The city portal is a good way to escape without paying; it wouldn't be good if they removed it.
And what's wrong with teleport? It seems to work normally, teleporting both allies and enemies. (I haven't checked in 3.51 yet, but I doubt they messed up the teleport).

Added after 3 minutes

P.S.
Guys, you could always use the "City Portal" spell in all versions (I don't know about Ique, I only downloaded it yesterday). There was also a picture showing the number of lost/killed troops, and it said "the enemy fled using magic" (or something like that), and there was a different animation on the picture.

Well, that's good if they didn't remove it, and the picture is indeed different; it shows the hero being surrounded, and then he suddenly disappears