As early as August 9th, 2017, the devs stated they’d want to replace the Grille 15. They’re probably close to that change, since in the 1.0.2 CT, we have a new icon.
Dev diaries, August 9th, 2017:
There were a lot of questions regarding the Grille. We were really close to implementing another variant in 9.20 or the next one. We honestly admit that we decided not to hasten it. We have to test more variants in internal tests. That means that drastic changes, or maybe swapping for another tank, should be expected at the end of the year.
This is the icon on the CT
Some time ago WG wanted to make some changes in the IS-4 heavy line, swapping their places.
The IS-4 in-game now has a different turret.
And this is how the ST-I looks like