Legal aspects of modding.

O_o
What about the "consumer protection law"? If they don't allow the use of one of the game's built-in features, they should refund the money and pay a penalty...
There's one fundamental thing to understand when communicating with them. All these rules they come up with are just nonsense. Copyright restricts the sale and distribution of content; everything else is just fantasy. Even if such clauses are included in the license agreement (and I don't believe that the Heroes 5 license agreement contains a clause prohibiting modifications after the release of the next game), it doesn't have any legal force, according to the laws of any country.

https://legal.ubi.com/termsofuse/ru-RU
Support refers to clause 3.1, stating that Heroes 5 is considered a service, and the new Ubisoft license is general for all products and supersedes old licenses.
I pointed out clause 6 to them, and they said that this clause only applies to new products, and if a new product is released in the series, the old product immediately loses the privileges of clause 6, and clause 3.1 applies to it.
I will get the final answer and send the entire correspondence to Ubisoft's headquarters. I'm interested in what the headquarters will say about such behavior from support and whether they are aware of all this or if it's just a quirk of the Russian support team.