Yes, you can. So, after the S26 is released, the One UI 8.5 will start rolling out for older models. The exact date for specific models are not known. I think it's too early to predict things so accurate...usually it's in the order: new to old. The n...
The new one because it's new & fresh. The old one is cool but I get bored with after seeing it too many times - It was too simple. The older one on Android 11 One UI 3.1 was cool - I like it.