Good day everyone,
So, despite news that the new branch of rear-turreted Soviet heavies would be branching off of the KV-13, posts on the RU forums have now indicated that this may not be the final decision, and that the developers are looking to branch them off from the IS:
Friends, pay attention to important information! We listened to your feedback, and at the moment we decided that a new branch of Soviet heavy tanks (Obj. 705A branch) will be explored through the IS, not through the KV-13. Also please note that this decision is not final and may change.
As stated, there seems to be no real final decision on the matter, so I’m sure we’ll be hearing more in the near future.